How Belief Works

Chapter 5: How Beliefs Form​

The vindication of a radical, and disregarded, 340-year-old theory​

In chapter 3 I raised the question of why we believe what we believe. And I showed that, as a matter of surprisingly basic logic, the current understanding that we believe claim X because we’ve assessed that X is true is wrong, because the reality is actually the other way around. But at the end of the chapter I raised another possibility: we believe X not because we've concluded that X is true, but simply because we've concluded X. That is, we believe X because X was the product of our reasoning. As I explained, even the formation of beliefs about the nature of, and events in, our surroundings via perception involves at least some reasoning about the content of our perceptions. However, as I pointed-out, although this theory of belief formation can seem true by definition and therefore unimpeachable, so can the theory that we believe something because we’ve assessed that it’s true. Indeed, I discovered that even the former is fatally logically flawed. And the counterintuitive truth about how beliefs form has profound implications for human psychology and therefore also our lives.

The distinction between a claim and its content

Consider first the distinction between a claim and its content.

As I stated in chapter 2, although a claim can be about anything, all claims are ultimately about the same thing: reality. Again, reality consists of:

    • physical reality – the physical world

    • mental reality – the content of our mind and other minds, including concepts

    • mathematical reality – for example, 2 + 2 = 4

    • logical reality – for example, a logical implication of the claims Vegetarians don’t eat meat and Pork sausages contain meat is Vegetarians don't eat pork sausages.

Note again that:

  • claims can be about the physical and mental reality of the past, present or future

  • the interactions and relationships between people, and the creation and effects of rules, conventions, and norms, involves a combination of the above aspects of reality, and includes the theory and practice of ethics and politics

  • even something that exists solely in someone's imagination is part of reality, in the sense that it's part of mental reality

  • even a false claim is a claim about reality – it's just that this claim about reality is false

  • even the claim that something has a particular sub-certain probability is a claim about reality: although the claim is stating that the thing in question is a mere possibility, the claim that that thing is possible as opposed to impossible, and has sub-certain probability P as opposed to some other sub-certain probability, is a claim about reality.

An analogy of a claim is a painting of a scene, given that both convey information about reality, however accurately. That is, just as a claim is a linguistic representation of part of reality, a painting of a scene is a pictorial representation of part of reality. Indeed, we sometimes say that a particular description 'paints a picture'. Even if the scene in a painting only exists in the artist's imagination, the painting is then a pictorial representation of the reality of the content of their imagination.

Now consider the distinction between a painting of a scene and the content of the painting. That is, whereas the former is ultimately just patches of paint on a surface, the latter is the scene that we see in the painting, and which to some degree matches a scene in either the physical world or the painter's imagination. And there's an analogous distinction between a claim and its content. That is, a claim, being an assertion, consists of a sentence, which consists of words and punctuation marks, which are analogous to the patches of paint which make-up the painting. But the content of the claim is what is being asserted by that sentence. For example, whereas the claim that David is vegetarian consists of the sentence David is vegetarian, its content is David being vegetarian.

It might be thought that the distinction between a claim and its content means that there's a distinction between the meaning of wordings such as:

her belief of the claim David is vegetarian

and

her belief that David is vegetarian.

That is, even though we use such wordings to refer to the same mental state, the former refers to the claim David is vegetarian, whereas the latter seems to instead refer to that claim's content. However, the latter wording actually also refers to the claim, rather than its content, because it involves the wording 'David is vegetarian', not 'David being vegetarian'. That is, the latter wording just doesn't refer to this claim as a claim, as the former wording does. So there's no distinction between the meaning of wordings of the form 'belief of the claim X' and 'belief that X'. And the same applies to wordings of the form 'confidence in claim X' and 'confidence that X', and of the form 'claim X is true' and 'it's true that X'.

Thinking X versus thinking about X

Now consider the difference between thinking claim X and thinking about X.

Thinking X is the mental state of believing X. For example, thinking 'David is vegetarian' is the mental state of believing that David is vegetarian. Indeed, we often use the word 'think' to refer to our, or someone else's, belief of something. For example, we may refer to Amy’s belief that David is vegetarian by saying ‘Amy thinks that David is vegetarian’.

It might be objected that although believing X necessarily involves thinking X, the reverse isn't true. For example, it can seem obvious that if we believe that David isn’t vegetarian, then we won’t reverse that belief simply by deliberately thinking 'David is vegetarian', like a mantra. However, I'm currently only concerned with thinking X in the sense of doing so organically, as part of our chain of thinking. And it’s this sense that I mean when I refer to thinking X, unless I state otherwise. I'll return later to thinking X in the sense of doing so because we decided to think this claim, like a mantra.

Now consider thinking about X. Whereas thinking X is the mental state of believing X, we can think about X while not believing X. For example, we can think about the claim David is vegetarian while not believing that David is vegetarian. We can actually also think about X without X existing in our mind. That is, if we know about the existence of X but don't currently know what it states, then we can at least think about X in the sense of thinking about its existence. For example, we may know that David said something to Amy about his dietary requirements, but not know what he said. However, I'm concerned here with thinking about X in the sense of thinking about this sentence as it exists in our mind – that is, contemplating X. And it’s this sense that I mean when I refer to thinking about X, unless I state otherwise.

It might be thought that if claim Y concerns claim X – as with the claim Amy said that David is vegetarian – then thinking Y is another sense of thinking about X, in addition to contemplating X and thinking about the existence of X. However, given that thinking the word sequence 'Amy said that David is vegetarian' involves thinking the word sequence 'David is vegetarian', it doesn't in itself involve thinking about the word sequence 'David is vegetarian', and therefore actually doesn't in itself involve thinking about the claim David is vegetarian. Although, given the speediness of the brain, which works on the timescale of milliseconds, we may think about the claim David is vegetarian so soon before or after thinking 'Amy said that David is vegetarian' that thinking 'Amy said that David is vegetarian' can seem to involve in itself thinking about the claim David is vegetarian. So even though claim Y concerns claim X, and thinking Y involves X existing in our mind, it doesn't in itself constitute another sense of thinking about X. Thinking Y only involves in itself thinking about X in the sense of thinking about its existence. That is, in the example, thinking 'Amy said that David is vegetarian' involves thinking about someone having said something, and therefore involves in itself thinking about the claim David is vegetarian in the sense of thinking about its existence. The only way that the existence of Y in our mind can involve thinking about X not merely in the sense of thinking about the existence of X is if we're thinking about Y in the sense of contemplating Y, which involves contemplating X. In the example, thinking about, in the sense of contemplating, the claim Amy said that David is vegetarian involves thinking about, in the sense of contemplating, the claim David is vegetarian.

Consider the difference between thinking X and thinking about – contemplating – X in terms of the distinction between a claim and its content. Thinking about X involves thinking about both this claim and its content. For example, thinking about the claim David is vegetarian involves thinking about both the sentence David is vegetarian and David being vegetarian, whether we're contemplating this claim or thinking a claim concerning it. And we can think about David being vegetarian without believing that David is vegetarian. However, thinking X involves thinking only about the content of this claim. For example, thinking 'David is vegetarian' involves thinking about David being vegetarian, but doesn't involve thinking about the sentence David is vegetarian. So although thinking X involves in itself X existing in our mind, it doesn't in itself involve thinking about X. If we're thinking about X while apparently thinking X, then we're actually not at that moment thinking X. Although, given the speediness of the brain, we may think about X so soon after thinking X that thinking X can seem to involve in itself thinking about X.

All of this reveals another logical flaw in the theory of degrees of belief, in addition to the two that I explained in chapter 4. Again, according to this theory, our confidence in claim X constitutes our belief of X if that confidence is above a particular sub-certain level. However, whereas thinking/believing X involves thinking about only the content of this claim, and therefore not about the claim itself, our confidence in X is a feeling about this claim. Our confidence in X is a feeling about whether X. Therefore, whereas thinking/believing 'David is vegetarian' involves thinking only about David being vegetarian, and therefore not about the claim David is vegetarian, our confidence in the claim David is vegetarian is a feeling about whether David is vegetarian, and is therefore a feeling about the claim David is vegetarian. Indeed, it wouldn't make sense to state that our confidence in the claim David is vegetarian is 'a feeling about whether David being vegetarian'. Someone might refer to 'confidence in David being vegetarian'. But they'd still be referring to a feeling about whether David is vegetarian, given that 'a feeling about whether David being vegetarian' is nonsensical. And a feeling about whether David is vegetarian is actually confidence in the claim David is vegetarian. That is, the wording 'confidence in David being vegetarian' is actually wrong – just as it's wrong to refer to belief X as 'the belief that X is true'.

The two ways that the content of a claim can exist in our mind

Now consider how the content of claim X exists in our mind when we're thinking X or thinking about X. It can seem true by definition that the only way for the content of X to exist in our mind is as the content of X. However, the existence of the content of X in our mind as the content of X constitutes thinking about X. Therefore thinking X, which doesn't involve thinking about X, can't in itself involve the content of X existing in our mind as the content of X. That is, although thinking X involves thinking about the content of X, it can't in itself involve thinking about the content of X being the content of X. But if, as we're thinking X, the content of X doesn't exist in our mind as the content of X, then in what alternative way does it exist in our mind? To understand the answer to this question, consider again the analogy of a painting of a scene.

Imagine that a photorealistic painting of an outdoor scene is used to try to create the illusion of a window in a room. The canvas is translucent and backlit, and the painting is framed using a window frame, without any space between the edge of the painting and the frame. This fake window is then attached to the wall opposite the entrance to the room, so that upon entering the room we're looking at the fake window face-on. The content of the painting is what we'd see, from the room entrance, through a real window located where the fake window is. And that outdoor scene is one in which an absence of any movement won't seem odd, at least initially.

This photograph is actually of a real window that looks somewhat like a backlit painting, but it illustrates how one can be confused for the other.

If upon entering the room and looking at the fake window the illusion is successful, at least in that moment, then our visual experience at that moment will consist of seeing a real outdoor scene through a real window. And if the illusion isn’t successful then our visual experience at that moment will consist of seeing merely a picture of an outdoor scene in a fake window. That is, at that moment, the content of the painting exists in our vision either as a real outdoor scene or as the content of a picture of an outdoor scene. And these are the only two logically possible ways that the content of the painting can exist in our vision. If, as we’re seeing the outdoor scene in the painting, our visual experience doesn’t consist of seeing a picture of an outdoor scene, then the only other logical possibility is that it consists of directly seeing a real outdoor scene – and vice versa. That is, if the content of the painting doesn't exist in our vision as the content of a picture of an outdoor scene, then the only other logical possibility is that it exists in our vision as a real outdoor scene – and vice versa.

Similarly, if a claim exists in our mind, then its content can exist in our mind as either the content of that claim or as part of reality. That is, whereas thinking about claim X involves the content of X existing our mind as the content of this claim, thinking/believing X involves the content of X existing in our mind as part of reality. And these are the only two logically possible ways that the content of a claim can exist in our mind.

For example, when we're thinking about the claim David is vegetarian, the content of this claim – David being vegetarian – exists in our mind as the content of this claim. But when we're thinking/believing 'David is vegetarian', the content of this claim exists in our mind not as the content of this claim, but as part of reality. Although, again, given the speediness of the brain, we may think about claim X so soon after thinking X that thinking X can seem to involve thinking about X. And thus thinking/believing X can seem to involve the content of this claim existing in our mind as the content of this claim.

So thinking/believing X doesn't in itself involve the content of X existing in our mind as a claim's content that matches reality. Indeed, that constitutes, by definition, the content of X existing in our mind as the content of a true claim, which is the mental state of believing that X is true. That is, it's the mental state of thinking/believing not claim X but the claim X is true. As I explained in chapter 3, the beliefs X and X is true are different beliefs, given that the claims X and X is true are different claims.

Likewise, thinking/believing X therefore doesn't in itself involve the content of X existing in our mind as the content of a claim that we believe. Indeed, that constitutes the mental state not of believing X, but of believing that we believe X.

The conclusion that thinking/believing X involves the content of X existing our mind as part of reality is compatible with my definition of belief, in chapter 2, as an understanding of part of reality. It also accords with my argument, in chapter 4, for the second flaw in the theory of degrees of belief – that confidence and belief are different kinds of mental states, and so no level of confidence in a claim, even certainty, can itself constitute our belief of the claim. I explained that whereas confidence, being a feeling, is an emotional mental state, belief, being an understanding of part of reality, is in itself a purely intellectual mental state. And the existence of the content of X in our mind as part of reality, as we're thinking/believing X, is indeed in itself an unemotional, and purely intellectual, mental state.

Also, the existence of the content of X in our mind, during the mental state of thinking/believing X, as part of reality rather than as the content of a claim is a second difference between the beliefs X and X is true. That is, not only do these beliefs involve different claims, but the latter belief involves the content of X existing in our mind as the content of a claim – a true claim. When thinking/believing 'X is true', it's the content of the claim X is true that exists in our mind as part of reality rather than as the content of a claim.

Also, regarding disbelief, the mental state of disbelieving X obviously doesn't involve the content of X existing in our mind as part of reality, and so involves that content existing in our mind as the content of a claim. Indeed, whereas believing X doesn't in itself involve believing that X is true, disbelieving X in itself involves believing that X is false, which involves the content of X existing in our mind as the content of a claim – a false claim.

Thinking X is always believing X

As I mentioned, the analysis so far has only been concerned with thinking claim X in the sense of doing so organically, as part of our chain of thinking, and therefore hasn't been concerned with thinking X in the sense of doing so because we decided to think this claim, like a mantra. And, again, it can seem obvious that, whereas organically thinking X is the mental state of believing X, deliberately thinking X doesn't cause us to believe X. However, the logic of the analysis so far, and the conclusion that thinking X involves the content of X existing in our mind as part of reality, applies equally to deliberately thinking X.

Even deliberately thinking X, like a mantra, doesn't in itself involve thinking about X. That is, although deliberately thinking X involves, by definition, thinking about this claim immediately beforehand, and we may also think about this claim immediately afterwards, it itself involves, equally by definition, thinking only about the content of this claim. For example, deliberately thinking 'David is vegetarian' involves in itself thinking only about David being vegetarian, and therefore doesn't in itself involve thinking about the sentence David is vegetarian. So although deliberately thinking X involves in itself X existing in our mind, it doesn't in itself involve thinking about X. Again, if we're thinking about X while apparently thinking X, then we're actually not at that moment thinking X. Although, given the speediness of the brain, we may think about X so soon before, and perhaps after, deliberately thinking X that deliberately thinking X can seem to involve in itself thinking about X.

And, again, the existence of the content of X in our mind as the content of X constitutes thinking about X. Therefore deliberately thinking X can't in itself involve the content of X existing in our mind as the content of X. That is, although deliberately thinking X involves thinking about the content of X, it can't in itself involve thinking about the content of X being the content of X. And the only other logically possible way that the content of X can exist in our mind is as part of realitywhich is the mental state of believing X. Therefore even deliberately thinking X, like a mantra, necessarily involves believing X. And our memory ensures that this inclusion of the content of X into our understanding of reality continues beyond us thinking X.

This conclusion can seem obviously contrary to our experience. Again, it can seem obvious, for example, that if we believe that David isn’t vegetarian, then we won’t reverse that belief simply by deliberately thinking 'David is vegetarian', like a mantra. However, consider again the speediness of the brain. In the example, immediately after deliberately thinking 'David is vegetarian' we’ll be aware that we were just then thinking this claim only because we decided to do so, like a mantra, despite believing the opposite, and therefore not because we've reason to believe that David is vegetarian. And that immediate awareness will lead us to organically think/believe 'David isn't vegetarian' within a fraction of a second of us deliberately thinking/believing 'David is vegetarian'. Therefore our belief that David is vegetarian will only last a fraction of a second, and so we'll normally have no awareness of it. And the same applies whenever we deliberately think a claim that's contrary to what we believe immediately before doing so.

We may also deliberately think claim X when we don’t have a belief about the subject of X immediately before doing so. Immediately after doing so we’ll be aware that we were just then thinking X only because we decided to do so, like a mantra, despite not having a belief about the subject of X, and therefore not because we've reason to believe X. And, given the speediness of the brain, that immediate awareness will lead us to organically think/believe a claim that expresses ignorance about the subject of X within a fraction of a second of us deliberately thinking/believing X. Therefore our belief of X will only last a fraction of a second, and so we'll normally have no awareness of it.

We may also deliberately think claim X when we already believe X. Immediately after doing so we’ll be aware that we were just then thinking X only because we decided to do so, like a mantra. But we'll also be aware that we believed X before deliberately thinking X. Therefore there's no reason for us to cease believing X just after deliberately thinking/believing X. However, it still won't be apparent that our deliberately thinking X necessarily involved believing X, given that we can attribute our subsequent belief of X to our belief of X immediately before deliberately thinking X.

Our extreme credulity

Now consider the entrance of a claim into our mind. As I stated in chapter 1, a claim enters our mind via one of four mental processes:

    • comprehension – when the claim is communicated to us via some medium that we perceive, which is normally voice or text

    • reasoning – when we generate the claim using logic, whether the logic is good or bad

    • imagination – when we generate the claim without using logic

    • recollection – when we recall the claim.

And if claim X exists in our mind we must be either thinking X or thinking about X, given that there’s no other possibility. Therefore the entrance of X into our mind must consist of us either thinking X or thinking about X. But can it be either, or are we always thinking X, or always thinking about X, upon X entering our mind? Consider first thinking about X.

It might be thought that the whole process of comprehending X involves, by definition, thinking about X. However, it actually involves first the collection, via our sense organs, of information about speech sounds or textual symbols, or whatever is communicating X, and then the analysis of that information by the language areas of our brain, in order to determine X. We aren't able to think about X until it has been outputted from this process into our mind. This is perhaps more obvious if we consider that thinking about X is contemplating X, and we can't contemplate a claim that we're comprehending until we've comprehended it. The process of comprehending X only involves thinking about X in the sense of thinking about the existence of this claim that we’re trying to comprehend. Of course, when we’re part-way through comprehending X we can contemplate the part that we’ve comprehended so far, but contemplating X itself obviously requires us to have comprehended the whole claim.

Thinking about X is itself a mental process, given that contemplating X involves mentally processing X. Any process, whether mental or physical, involves the processing of the input to the process, which produces an output:

For example, the process of book manufacturing involves the processing of paper, ink and other materials – the inputs – to produce a book – the output. In the case of thinking about X, the main input to this process is obviously X – the other inputs being related information stored in our memory – and any output is claim Y about X, whether Y is generated by our reasoning or imagination, or is recalled. And an input to a process can itself be the output of another process:

In the case of book manufacturing, the paper, ink and other materials are themselves the outputs of other processes. In the case of thinking about X, X is itself the output of the mental process of either comprehension, reasoning, imagination, or recollection:

The outputting of X by the first process and the processing of X by the second are obviously different events, given that they involve different processes and are different kinds of events. But the outputting of X by the first process is the entrance of X into our mind, and the processing of X by the second process is us thinking about X. Therefore the entrance of X into our mind can't itself ever consist of us thinking about X. Although, given the speediness of the brain, we can begin thinking about X within a fraction of a second of X entering our mind, and so it can seem that we were doing so upon X entering our mind.

It might be objected that the completion of the first process could in itself, at least sometimes, also be the beginning of the second. That is, the entrance of X into our mind, upon being outputted by the first process, could be the entrance of X into the process of thinking about X. Consider the following analogy. When someone walks through a doorway connecting two adjacent rooms, their crossing of the threshold is both them exiting one room and them entering another. Therefore, even though exiting a room is the opposite of entering a room, they can be the same event. Similarly, even though outputting from a process is the opposite of inputting into a process, the outputting of X from the first process could itself also be the inputting of X into the second.

However, first, the analogy doesn't work. Although walking involves innumerable processes inside the body, someone walking out of the first room doesn't constitute them being outputted by some process, and their walking into the second room doesn't constitute them being inputted into some process. Therefore their simultaneous exiting the first room and entering the second can't be an analogy of X being outputted from the first process and inputted into the second.

Also, unlike exiting and entering, outputting and inputting can't be the same event.

When someone walks through a doorway connecting two adjacent rooms, their exiting the first room and entering the second are merely different perspectives of the same event – the person walking through the doorway – rather than different events. Exiting any space involves in itself entering another space, and vice versa. Even when someone walks from one room to another via a corridor, their exiting the first room is also their entering the corridor, and their entering the second room is also their exiting the corridor. Even when someone walks out of a building, their exiting the building is also their entering the area immediately outside. Therefore neither exiting or entering can occur without involving in itself the other.

Now consider the output of one process being an input to another. That outputting is the completion of the formation of something, whereas that inputting is the beginning of the processing of that thing. And the formation of something and the processing of that thing are different kinds of events involving the same thing, rather than different perspectives of the same event. Consider the output of a process only being inputted into another process five minutes after being outputted. That outputting doesn't itself also involve inputting, and that inputting doesn't itself also involve outputting. And if outputting and inputting can each occur without itself also involving the other, then they're different kinds of events. And different kinds of events can't, by definition, ever be the same event. Therefore outputting and inputting can't ever be the same event, although they can be immediately consecutive. Different kinds of events can of course occur simultaneously, but if the output of one process is an input to another, and that outputting isn’t itself that inputting, then that inputting can only occur after the outputting has occurred.

Therefore the outputting of X from the first process can't itself ever also be the inputting of X into the second, although they can be immediately consecutive. That is, the entrance of X into our mind can't ever be the entrance of X into the process of thinking about X.

It might then be objected that, even though the completion of the first process indeed can't in itself ever also be the beginning of the second, the entrance of X into our mind could still, at least sometimes, be the entrance of X into the process of thinking about X. That is, perhaps X, at least sometimes, doesn't actually enter our mind until it enters the second process.

However, the output of the process of reasoning is, by definition, a conclusion, and forming a conclusion involves, by definition, the entrance of a claim into our mind. Likewise, the output of the processes of comprehending, imagining-up and recalling a claim involve, by definition, the entrance of that claim into our mind. Therefore the outputting of X from the first process is, by definition, the entrance of X into our mind.

It's possible that upon X being created, recreated or retrieved by the first process it must then be transmitted to some central processing area of the brain in order to enter the mind. But if so then that would merely mean that the transmission of X to this area is the last stage of the first process, given that the outputting of X from the first process is, by definition, the entrance of X into our mind.

It might then be countered that, even though concluding X, comprehending X, imagining-up X and recalling X indeed involve, by definition, the entrance of X into our mind, they may not necessarily involve just the first process, and could also involve, at least sometimes, the entrance of X into the second. However, consider that forming a conclusion, and comprehending, imagining-up and recalling a claim, are mental tasks.

The performance of any kind of task – whether by our minds, or our minds and bodies, or a machineconstitutes a single process. That is, the beginning of the performance of the task is the beginning of that process, and the completion of the task is the completion of that process. The performance of the task may involve the performance of sub-tasks, with such activities therefore constituting sub-processes. And the task may itself be a sub-task, with the performance of the task therefore itself constituting a sub-process. But the performance of the task constitutes a single process even if that process involves sub-processes or constitutes one, or both.

So our performance of the mental task of forming a conclusion, or comprehending, imagining-up or recalling a claim, constitutes a single process, with our completion of each task therefore being the completion of that process, which involves the entrance of the claim into our mind. Indeed, we refer to 'the process' of forming a conclusion, or of comprehending, imagining-up or recalling a claim. Therefore concluding X, comprehending X, imagining-up X and recalling X can't ever consist of the first process and the beginning of the second. First, that wouldn't constitute a single process. Although two consecutive processes can, as a whole, constitute a single process composed of two sub-processes, one process and merely the beginning of a second can't constitute a single process. Second, the completion of each task would be the beginning, rather than the completion, of a process. Therefore concluding X, comprehending X, imagining-up X and recalling X, which involve the entrance of X into our mind, indeed always solely involve the first process.

These objections therefore fail to challenge the conclusion that the entrance of X into our mind, via any mental process, can't itself ever consist of us thinking about X. And, again, if X exists in our mind we must be either thinking X or thinking about X, given that there’s no other possibility. Therefore the entrance of X into our mind, via any mental process, must always consist of us thinking X. Indeed, the thought X isn't itself a mental process, but is the output of a mental process. That is, not only does thinking X not itself involve mentally processing X – which is thinking about X – it also doesn't itself involve the processing of any input to produce an output, and is instead the outputting of X from a mental process.

Regarding the entrance of X into our mind via reasoning, to conclude X is, by definition, to think X. But the idea that the entrance of X into our mind via comprehension, recollection, or imagination doesn't consist of us thinking about X, and instead consists of us thinking X, can seem obviously contrary to our experience. However, the implication of the above logic is that this apparent experience is contrary to reality, and therefore must be due to us thinking about X so quickly after X enters our mind that it seems that we were doing so upon X entering our mind.

Of course, the conclusion that the entrance of X into our mind, via any mental process, always consists of us thinking X, together with the preceding conclusion that thinking X is always believing X, leads to the even more counterintuitive conclusion that the entrance of X into our mind, via any mental process, always involves us believing X. And an implication of the analysis in the previous two sections is that our belief of X upon X entering our mind, via any mental process, is always due merely to that entrance, rather than being due to X being the product of the mental process that led to that entrance. That is, that analysis, in showing that thinking X is always believing X, didn't refer to the mental process that leads to us thinking X, and only considered how the content of X exists in our mind as we're thinking X. And if thinking X is always believing X due to how the content of X exists in our mind as we're thinking X, then our belief of X as we think X upon X entering our mind can't ever not be due to how the content of X exists in our mind at this moment – and therefore can't ever be due to X being the product of the mental process that led to that entrance.

Therefore the mere entrance of a claim into our mind, whether via reasoning, comprehension, imagination or recollection, causes us to believe it. And our memory ensures that this inclusion of the content of the claim into our understanding of reality continues beyond the claim's entrance into our mind. I call this theory of belief formation credulism, given its extreme claim about our credulity.

As I mentioned in chapter 1, the apparent unbelievability of credulism can itself seem to disprove it. The theory can seem obviously contrary to both the concept and experience of comprehending, imagining-up or recalling a claim. Regarding reasoning, a conclusion is by definition a belief. However, the idea that our belief of this claim upon it entering our mind is due merely to that entrance, rather than being due to the claim being the product of our reasoning, can seem obviously contrary to both the concept and experience of reasoning. I address these points after the next section.

The logical necessity of credulism

Credulism is counterintuitive in another way. The above theoretical argument consists solely of conceptual analysis – that is, the chain of logic doesn't at any point depend on observational evidence. It therefore reveals not only our extreme credulity, but also that this is so not because of the nature of the human brain, but simply by logical necessity.

Again, the central tenet of the field of psychology today is that how the human mind works is solely due to the wiring and chemistry of the human brain, which is in turn determined by a person’s genes and experiences. Therefore all mainstream theories about any aspect of the functioning of the human mind involve that aspect being due, in some way, to the nature of the human brain. However, although our capacity for belief is obviously due to the nature of the human brain – rocks can't hold beliefs – there isn’t anything about the human brain which causes our extreme credulity. Instead, that extreme credulity is simply a logically inherent, and therefore inevitable, feature of a claim entering a mind, for any form of intelligence.

The logical necessity of credulism, and of the certainty of belief, and therefore also of their implications for human psychology, implies a previously unknown distinction between human psychology and human nature. Human nature is the product of evolution by natural selection. But if some aspects of human psychology are due solely to logical necessity, then human nature is only part of human psychology.

Credulism and comprehending, imagining-up or recalling a claim

Again, credulism can seem obviously contrary to both the concept and experience of comprehending, imagining-up or recalling a claim. However, consider comprehending a claim.

The concept of comprehending a claim isn't about the claim being believed – it's simply about the claim being understood. However, the fact that this concept isn't about the claim being believed doesn't mean that comprehending a claim can't involve the claim being believed. That is, although the idea that comprehending a claim causes us to believe it is counterintuitive, there isn't actually anything about the concept of comprehending a claim that excludes this possibility. Therefore credulism actually isn't contrary to the concept of comprehending a claim.

However, it can seem obvious from our experience of comprehending claims that doing so doesn't cause us to believe them. For example, it can seem obvious from our experience of comprehending the obviously false claim Paris is the capital of Germany that doing so doesn't cause us to believe that Paris is the capital of Germany. But it’s important to bear in mind two things. First, credulism doesn’t state that our belief of a claim, upon it entering our mind, is permanent. Second, again, the brain works on the timescale of milliseconds. In the example, although the claim Paris is the capital of Germany is obviously false, its falseness is of course only apparent to us after we've comprehended and then assessed it. We believe the claim upon comprehending it, but its obvious falseness means that this belief only lasts the fraction of a second that it takes our reasoning to generate the contrary claim Paris isn’t the capital of Germany. This reasoning will involve recognising that the claim Paris is the capital of Germany is contrary to the web of consistent beliefs which make-up our understanding of reality – specifically, beliefs such as Paris is located in France, Paris is the capital of, and only of, France, and Berlin is the capital of Germany. And given the extreme briefness of our belief that Paris is the capital of Germany, we've no awareness of it. The same applies to our comprehension of any claim that seems obviously false.

The same also applies to our comprehension of claims that seem obviously uncertain. For example, even if the claim Matt will win the chess game seems obviously uncertain, its uncertainty is of course only apparent to us after we've comprehended and then assessed it. We'll believe the upon comprehending it, but its obvious uncertainty means that this belief will only last the fraction of a second that it takes our reasoning to generate a contrary claim such as It's uncertain that Matt will win the chess game. And given the extreme briefness of our belief that Matt will win the chess game, we'll have no awareness of it.

We also comprehend claims that don't seem obviously false or obviously uncertain, and that we didn't already believe. For example, upon being told by a colleague that they went to the cinema the previous evening we may not immediately think of a reason to disbelieve or even doubt this. Therefore our belief of their claim upon comprehending it won't be replaced by a contrary belief within a fraction of a second of forming. However, although our belief of such a claim, upon comprehending it, can therefore last long enough for us to be able to be aware of it, and therefore also aware of our credulity, there are two main reasons why we tend not to be aware of either even in such cases:

  • The certainty of belief:

If uncertain belief was possible then the inherent doubt involved in an uncertain belief would motivate us to think about our holding of it. But the certainty of belief means that we tend to be focussed on the apparent reality that is the content of our beliefs, and therefore tend not to be also thinking about our belief of that content. That is, we tend not to be thinking about the content of one of our beliefs as being the content of one of our beliefs. Therefore even when our belief of claim X lasts long enough for us to be able to be aware of it, we tend not to be. That is, following the formation of the belief, we tend to be only thinking about the apparent aspect of reality that is its content, and its implications. And we of course can't be aware of our credulity in the formation of our belief of X if we aren't aware of our belief of X.

Also, if uncertain belief was possible then the inherent doubt involved in an uncertain belief would also motivate us to think about how it formed. But the certainty of belief means that even when we're aware of our belief of X we tend not to be motivated to think about how it formed. And we of course can't be aware of our credulity in the formation of our belief of X if we don't think about how this belief formed.

Regarding other people's beliefs, we're naturally motivated to try to understand the world around us, which includes other people, and so we're naturally motivated to think about other people's beliefs and how they formed. Hence we're more likely to notice other people’s credulity than they are, or than we are to notice our own credulity.

  • Cognitive busyness:

Our minimum waking cognitive activity involves continuously trying to work-out:

  • what's happening in the immediate present, often including the contents of other people’s minds

  • why it's happening

  • what's likely to happen in the next few moments, often including the contents of other people’s minds

  • what should be our goals for the next few moments, taking into account our longer-term goals

  • how best to act in the immediate future in order to achieve our goals, often including what to say to people.

This cognitive activity involves a constant stream of belief formation – and, again, it's just our minimum waking cognitive activity. And our degree of cognitive busyness increases as the following factors increase:

  • time pressure

  • the quantity of information being processed

  • the difficulty of the current cognitive task – which increases as stress, tiredness or distraction increases

  • the number of cognitive tasks being performed in parallel.

Given all of this, we’re usually too cognitively busy thinking about the content of our beliefs, and trying to make inferences from them, and from our perceptions, to think about our belief of that content. And, again, we of course can't be aware of our credulity in the formation of our belief of claim X if we aren't aware of our belief of X. Also, even when we're aware of our belief of X we're usually too cognitively busy to think about how it formed. And, again, we of course can't be aware of our credulity in the formation of our belief of X if we don't think about how this belief formed.

We can sometimes be so cognitively busy that even when we comprehend a claim that would normally seem obviously false or obviously uncertain our belief of it isn't replaced by a contrary belief within a fraction of a second of forming, and can last until our extreme level of cognitive busyness has reduced. That extreme cognitive busyness also means that, until it reduces, we'll usually not be aware of our belief of the claim and our credulity. But when it does reduce enough so that the claim suddenly seems obviously false or obviously uncertain our belief of it will therefore cease and we'll be surprised that we believed such claims.

In addition to the certainty of belief and cognitive busyness, the more mundane a believed claim, and therefore the less important the question of its truth, the less likely we are to be motivated to think about our belief of it and how that belief formed – and the vast majority of our beliefs are mundane, as in the example of our belief that our colleague went to the cinema the previous evening. Also, the more time that has passed since a belief formed, the less likely we are to think about this event, and thus the less likely we are to think about our belief of the claim and how it formed.

Also, even when we cease holding a belief that's lasted much longer than a fraction of a second, which involves thinking about this belief that we now consider false or uncertain, and feeling some degree of surprise at this revision of our understanding, we don’t necessarily analyse how our previous belief formed. And even if we do analyse the formation of one of our beliefs, past or present, which occurred when we comprehended the claim concerned, we may not remember that. And even if we do, we may assume that the belief formed just after our comprehension of the claim, as the product of either our reasoning or intuition.

In sum, when we comprehend a claim that we didn't already believe, our resulting belief of it either only lasts a fraction of a second, and we therefore have no awareness of it, or it lasts long enough for us to be able to be aware of it, and therefore also aware of our credulity, but even then we tend not to be aware of either. Therefore, although we're sometimes aware of our belief of a claim after we've comprehended it, and of our credulity upon comprehending it, credulism can seem obviously contrary to our overall experience of comprehending claims, even though it actually isn't.

The above counter to the objection that credulism seems obviously contrary to both the concept and experience of comprehending a claim similarly applies to the same objection regarding the concept and experience of imagining-up or recalling a claim. Again, the apparent unbelievability of credulism can itself seem to disprove it. In reality, we believe this theory upon comprehending it, but its apparently obvious falseness means that our belief only lasts the fraction of a second that it takes our reasoning to generate the conclusion that the theory is false.

Credulism and reasoning

Again, credulism can also seem obviously contrary to both the concept and experience of reasoning. Consider first the concept of reasoning.

Again, a conclusion is by definition a belief. But it can seem that, also by definition, our belief of this claim upon it entering our mind is due to the claim being the product of our reasoning, and is therefore not due merely to that entrance. However, consider that reasoning involves determining apparent logical implications of particular premises.

Although reasoning is the formation of beliefs using logic, and a belief is an understanding of part of reality, the task of determining an apparent logical implication of particular premises isn't itself concerned with the reality of the content of either those premises or an apparent logical implication of them, but is merely concerned with what follows logically from those premises. Therefore the process of determining an apparent logical implication doesn't itself explain our belief of that claim. According to the current conception of reasoning, we believe an apparent logical implication upon it entering our mind because we believe its premises as well as believing in our logic.

But the implication of credulism is that our belief of an apparent logical implication upon it entering our mind is actually due merely to that entrance. This doesn't mean that our belief of the premises, and belief in our logic, is irrelevant to the formation of this belief. When we form a conclusion our belief of our premises was necessary for us to use them as the basis of our reasoning. And our belief in our logic was necessary for us to apply it to our premises. And the application of our logic to our premises led to the entrance into our mind of the claim that we thereby believed. By definition, when we form a conclusion, our reasoning led to the formation of this belief. And, also by definition, that belief formation occurred upon the claim being produced by that reasoning. But we incorrectly infer from this that, also by definition, our belief of the claim upon it entering our mind was due to the claim being the product of that reasoning. In short, credulism is indeed contrary to the current conception of reasoning, but the implication of credulism is that that conception is wrong.

Now consider the experience of reasoning. It can seem from our experience of forming a conclusion that our belief of this claim upon it entering our mind is due to the claim being the product of our reasoning. However, this experience would actually be the same whether our belief of the claim upon it entering our mind is due to the claim being the product of our reasoning or the mere entrance of the claim into our mind. That is, either way, the experience is the same: us forming a belief via reasoning. The sense that our experience is of the belief formation being due to the claim being the product of our reasoning is actually an interpretation of this event based on the above false conception of reasoning.

We sometimes generate claims via logic that we either believe is flawed, questionable, based on false premises, or based on uncertain premises. For example, we knowingly apply flawed logic to particular premises when illustrating a logical fallacy. And we determine an apparent logical implication of premises that we either disbelieve or are uncertain about when undertaking hypothetical, 'What if...', reasoning. In such cases, the conclusion of our reasoning is either of the form The illogical [or possibly illogical] implication of the premises is X or of the form A logical implication of the false [or uncertain] premises is X. But although our conclusion isn't simply X, X enters our mind in the process of reaching this conclusion. And the idea that our generation of X in such cases involves believing X can seem just as obviously contrary to our experience as the idea that merely comprehending, imagining-up or recalling X involves believing X. However, given our belief about the nature or premises of the logic that we used to generate X, and the speediness of the brain, our belief of X only lasts the fraction of a second that it takes our reasoning to generate a contrary claim such as It's uncertain whether X. And given the extreme briefness of our belief of X, we've no awareness of it.

So not only, as I showed in chapter 3, is it not true that we believe X because we’ve assessed that X is true, it’s not even true, even sometimes, that we believe X because we've concluded X – that is, because X was the product of our reasoning – even though the latter theory, like the former, can seem true by definition and therefore unimpeachable. Instead, we believe X merely because X has entered our mind, whether via reasoning, comprehension, imagination or recollection.

Another potential objection

It might still be objected, regarding comprehending a claim that we didn't already believe, that it seems both obvious from experience and true by definition that our level of trust in the source of the claim affects whether we believe the claim when we comprehend it, contrary to credulism.

However, as I mentioned in the section 'Credulism and comprehending, imagining-up or recalling a claim', even if we're aware that one of our beliefs, past or present, formed when we comprehended the claim concerned, an unawareness of credulism may lead us to assume that the belief formed just after our comprehension of the claim, as the product of either our reasoning or intuition. Therefore we can assume that the formation of the belief was due to us reasoning, just after comprehending the claim, that the source of the claim is trustworthy, whether or not we recall such reasoning.

Also, if we distrust the source of claim X when we comprehend X, then our belief of X upon comprehending X will only last the fraction of a second that it takes, given the speediness of the brain, for our reasoning to generate a contrary claim such as It's uncertain whether X. And given the extreme briefness of our belief of X, we've no awareness of it. Therefore it can then seem that our distrust of the source of X prevented our belief of X.

In short, our level of trust in the source of a comprehended claim actually affects not whether we believe the claim when we comprehend it, but only whether we continue to believe it after we comprehend/believe it.

However, there's one scenario in which our trust in the source of a comprehended claim leads to our belief of the claim. If after comprehending/believing X we cease believing X for whatever reason, we may subsequently conclude, or remember, that we trust the source of X. And that trust might lead us to conclude that X must be true, and that we were therefore wrong to conclude otherwise. And concluding that X is a true claim leads us to conclude X. As I explained in chapter 3, although our belief of X can't be due to us assessing that X is true, concluding that X is true on the basis of our trust of its source doesn't actually constitute assessing that X is true, given that our conclusion is based on not a comparison of the content of X and reality, but a consideration of the source of X. But even in this scenario our trust in the source of the comprehended claim leads to our belief of the claim in a way that isn't contrary to credulism.

The above analysis similarly applies to the same objection regarding recalling a claim.

Credulism and supposedly intuitive beliefs

The concept of intuitive belief arose partly due to our unawareness of credulism.

As I explained in chapter 4, our supposed intuition, which is understood to be a kind of sixth sense, is a fiction. We often attribute a feeling or belief to our supposed intuition when it doesn't seem to be the product of perception or reasoning. However, the occurrence of any mental phenomenon is the product of a cognitive chain of events, whether or not we're aware of those events. For example, when an apparently random memory suddenly enters our mind it is in reality always triggered, however indirectly, by something in our current experience, even though we're not aware of what it was. In the case of feelings and beliefs that don't seem to be the product of perception or reasoning, we invented the concept of intuition to bridge this explanatory gap.

One reason for the explanatory gap is the speediness of the brain – which, again, works on the timescale of milliseconds. Regarding the formation of beliefs, a claim can enter our mind via a cognitive chain of events that's so short, and therefore brief, that we're subsequently only aware of the resulting belief – whether that cognitive chain of events is the process of reasoning, comprehension, imagination or recollection. But even when we're aware that a belief formed when the claim concerned entered our mind via the process of comprehension, imagination or recollection, our unawareness of credulism leads to an explanatory gap. Of course, when we're aware that a belief formed when the claim concerned entered our mind via our reasoning, we can attribute that belief to that reasoning.

Why credulism matters

If merely comprehending, imagining-up or recalling a claim involves believing it, and that belief can endure for any length of time without us being aware of our credulity, then that in itself obviously has profound implications for human psychology and therefore our lives. But, as I explained in chapter 4, the certainty of belief means that not only do we believe claim X upon it entering our mind, via any mental process, we always do so without any doubt. If there were degrees of belief then the entrance of the content of X in our mind as part of reality would involve a level of confidence in this apparent reality. Therefore our belief of X upon it entering our mind could at least sometimes have been an uncertain belief, and that uncertainty could have motivated us to investigate the truth of our new belief. But the logical impossibility of degrees of belief means that the content of X always simply exists in our mind as part of reality upon it entering our mind. Therefore we always believe X with certainty, in the sense of an absence of doubt, upon it entering our mind. Also, confirmation bias, which I mentioned in chapter 4, means that we're biased towards interpreting, seeking, and recalling information in a way that confirms, or helps to confirm, our new belief.

Again, given that belief is the centre of human psychology, the theories of credulism and the certainty of belief will together revolutionise the field of psychology, and therefore also have equally profound implications for every aspect of our lives. For example, as I mentioned in chapter 4, I discovered that, as I'll show in later chapters, these two theories about the psychology of belief together provide a unifying explanation of all cognitive biases, and therefore of the whole of human irrationality.

As I mentioned in chapter 1, the idea that the mere entrance of a claim into our mind causes us to believe it was first proposed by the prominent 17th-century philosopher Baruch Spinoza in his 1677 book Ethics.

Spinoza and the title page of his book Ethics

I also mentioned in chapter 1 that the most prominent modern academic writing on Spinoza’s theory is a 1991 paper called ‘How Mental Systems Believe’, which catalogues observational evidence, including experimental research, which seems to support the theory, and which I’ll cover in a later chapter. It was written by the Harvard psychology professor Daniel Gilbert, one of the rare academics who supports the theory.

Gilbert’s paper

However, Gilbert misunderstands Spinoza’s theory in one significant way: he thinks that it only applies to claims entering our mind via comprehension. This mistake is also made by the authors of most other articles and books which refer to the theory. In many cases, it seems that this is because the author based their understanding of the theory on either Gilbert’s paper or a paper or book written by someone who based their understanding of the theory on Gilbert's paper. For example, the psychology professor James Alcock, who’s an expert on belief, misrepresents the theory in this way in his 2018 book on belief, Belief that I referred to in chapter 1 citing Gilbert’s paper.

Strangely, there doesn’t seem to be an awareness within either psychology or philosophy of the profound, and revolutionary, implications of Spinoza's theory – and not just among those who are aware of it but don’t support it, but even among the very few who do support it. This will be partly due to the strange unawareness in academia, that I mentioned in chapter 1, that belief is the centre of human psychology, and to the general unawareness of the certainty of belief, and to the common misunderstanding that the theory only applies to claims entering our mind via comprehension. However, even after taking these factors into account, the failure to appreciate that such an extraordinary theory has extraordinary implications is still very odd. That is, even if one thinks that Spinoza's theory only applies to our comprehension of claims, it's obvious that we comprehend claims countless times during our everyday lives, whether the claim is written or spoken, and is significant or mundane. And even if one is unaware of the certainty of belief, there's no reason to think that our belief of a claim upon merely comprehending it would necessarily be an uncertain belief. Also, any degree of belief of a claim upon it merely comprehending it is a major difference from no belief of the claim. And even if one is unaware that belief is the centre of human psychology, belief is obviously a major aspect of human psychology.

Gilbert's paper is an example of this significant underappreciation of the implications of Spinoza's theory, given that he doesn't refer to the theory as having revolutionary, or even profound, implications. Indeed, he last published research on the theory in 1993, even though he's still an active researcher. He also doesn't refer in the paper to belief being the centre of human psychology, or to the non-existence of degrees of belief, in addition to restricting Spinoza's theory to comprehended claims.

In the above-mentioned book Belief, Alcock expresses support for Spinoza's theory, but only spends about one and a half of the book's 638 pages on it, and doesn't get to it until half-way through the book. And he merely introduces it, without considering even briefly the obvious and important question of why belief formation would work this way. And he doesn’t refer to it anywhere else in the book. As I mentioned in chapter 1, he doesn’t refer to belief being the centre of human psychology anywhere in the book. And, as I mentioned above, he only refers to Spinoza's theory applying to comprehended claims. And he refers to there being degrees of belief.

In the 2020 paper 'The science of belief: A progress report', that I mentioned in chapter 1, the cognitive scientists Nicolas Porot and Eric Mandelbaum also express support for Spinoza's theory. They do claim that the theory can explain many different, and significant, psychological phenomena – including confirmation bias – but they don't claim that it has the potential to revolutionise psychology. Indeed, the part of this survey paper on the psychology of belief that deals with this fundamental aspect of belief consists of only five paragraphs. As I mentioned in chapter 1, they don't refer to belief being the centre of human psychology. And it's unclear whether they appreciate that Spinoza's theory doesn't just apply to comprehending claims. That is, they don't refer to the theory as only applying to comprehending claims, but they cite Gilbert's paper without criticising his misunderstanding, and the hypothetical scenarios they use to illustrate the theory only involve claims being comprehended. And they don't refer to the non-existence of degrees of belief.

In the 2011 book The Believing Brain, which I mentioned in chapter 2, researcher and science writer Michael Shermer ‘… synthesizes [his] thirty years of research …’ on the psychology of belief. Shermer states in the introduction ‘Beliefs come first, explanations for beliefs follow’ and ‘The brain is a belief engine’. Given these statements, and the book's title, it might be assumed that the book is all about Spinozan belief formation. Indeed, Shermer expresses support for Spinoza's theory. However, he only spends two paragraphs on it, and doesn't get to it until half-way through the book, and he misunderstands it. And his own thesis about belief formation is actually much less radical than Spinoza's.

Shermer raises the question ‘Why do people believe?’, but his answer doesn’t mention that the mere entrance of a claim into our mind, whether via comprehension, reasoning, imagination or recollection, causes us to believe it. He instead just lists factors that influence what beliefs we form:

We form our beliefs for a variety of subjective, personal, emotional, and psychological reasons in the context of environments created by family, friends, colleagues, culture, and society at large ...

Indeed, in addition to presenting Spinoza's theory as only applying to comprehending claims, Shermer thinks that it states that ‘belief comes quickly’ – so our belief of a comprehended claim isn't immediate – and that we merely have a ‘tendency’ to believe – so our belief of a comprehended claim isn't even inevitable. Also, he doesn’t refer to belief being the centre of human psychology, or to the non-existence of degrees of belief. Given all of this, it's less surprising that he doesn't refer to Spinoza's theory as having revolutionary, or even profound, implications.

Vindicating Spinoza

Spinoza tried to support his theory using an obscure philosophical argument that I can't follow. It at one point refers to the geometry of a triangle, and at another point refers to an imaginary winged horse. According to this philosophy paper, which I only mostly can't follow, several modern philosophers have independently concluded that Spinoza's argument is flawed.

The essence of his argument is possibly that, logically, we can only think of a reason to disbelieve a claim after it has entered our mind and we’ve assessed it, and so we must believe the claim upon it entering our mind. However, not disbelieving a claim doesn't of course itself imply belief of the claim, given that it's possible to neither disbelieve or believe a claim.

The obscurity and apparent illogic of Spinoza’s argument partly explains why belief of his counterintuitive theory has, ironically, been negligible since it was published, and why most researchers in psychology and philosophy today haven’t even heard of it, and interest amongst those who have is low. One illustration of the current low status of the theory is that reference works on psychology or philosophy don’t refer to it, even briefly. For example, none of the over 1,700 entries in the online Stanford Encyclopedia of Philosophy refer to it – including the 14,000-word entry on belief and the 14,000-word entry on Spinoza. And neither do any of the almost 26,000 entries in the American Psychological Association’s Dictionary of Psychology. And neither do any of the philosophy or psychology university textbooks that I’ve checked.

Another illustration of the current low status of Spinoza's theory is the 2018 book The Oxford Handbook of Spinoza, published by Oxford University Press. According to the blurb, it's a collection of essays written by ‘many of the world’s leading Spinoza specialists’, which ‘grapple directly with Spinoza’s most important arguments’. And the book is edited by Spinoza expert, and philosophy professor, Michael Della Rocca. However, none of the twenty-six essays in this 687-page book is on Spinoza's theory of belief formation, which is only mentioned briefly a few times, and the word ‘belief’ isn’t listed in the book’s extensive index.

In the previously-mentioned 1991 paper How Mental Systems Believe, Gilbert doesn’t outline Spinoza’s theoretical argument, or even refer to it, despite offering an alternative theoretical argument. This strange omission is perhaps due to him being unable to follow Spinoza’s obscure logic. Gilbert's speculative argument involves our comprehension of claims being Spinozan for an evolutionary reason, rather than logical necessity, and has several flaws, in addition to not addressing the entrance of claims into our mind via reasoning, imagination and recollection.

He begins with the premise that to perceive something is to believe it. For example, to see a chair in front of us is to believe that there’s a chair in front of us. Therefore, he argues, such beliefs form before we’ve had a chance to reason about the content of the perception. He argues that we evolved to form such beliefs in this way because we often need to react quickly to our surroundings, and perception gives us a generally accurate understanding of our surroundings. He then states that perception is therefore 'quintessentially Spinozan'.

Gilbert next suggests that our cognitive faculty could have evolved from our perceptual faculty, given that both involve mental representations. In the case of perception the mental representations are the content of our perceptions, and in the case of cognition they’re the content of claims. Also, both the perceptual process and the process of comprehending claims involve processing sensory data to create a mental representation – in the case of comprehension, we must perceive the medium used to communicate the claim, which is normally voice or text. Gilbert then suggests that the Spinozan nature of perception could therefore have been inherited by the process of comprehending claims. That is, just as to perceive something is to believe it, to comprehend claim X is to believe X.

He then argues that most people communicate true claims most of the time, quoting the philosopher Daniel Dennett: ‘The faculty of communication would not gain ground in evolution unless it was by and large the faculty of transmitting true beliefs’. Therefore, Gilbert suggests, just as the general reliability of our perceptions allows us to immediately believe what we perceive, and thereby react quickly to our surroundings, so the general reliability of the claims that people communicate allows us to immediately believe what we comprehend, and thereby react quickly to those claims.

However, first, although the biological value, and therefore evolution, of communication indeed depends on most communicated claims being true, the communication of false claims, knowingly or not, obviously isn't an infrequent occurrence. And given that our belief of false claims will tend to have negative consequences for us, from minor to major, it seems implausible that the frequency of true communicated claims is sufficient to lead to the evolution of our automatic belief of every claim that we comprehend. Indeed, the greater the credulity in our species, the greater the biological value of taking advantage of that credulity by lying, and therefore the greater the evolutionary pressure towards a tendency to lie, and therefore, eventually, the greater the frequency of lying, and therefore the greater the evolutionary pressure away from credulity.

This point is used by the cognitive scientist Hugo Mercier in his 2020 book Not Born Yesterday, on gullibility, to argue that it can't be true that we automatically believe every claim that we comprehend. But this argument doesn't take into account the possibility that such extreme credulity is simply logically inevitable, and that its biological cost is therefore irrelevant to whether it occurs. That is, Mercier's reasoning is based on the previously-mentioned false assumption that how the human mind works is due solely to the nature of the human brain.

Mercier also argues against the idea that we have even a tendency to be gullible, by using 'the latest findings from experimental psychology to show how each of us is endowed with sophisticated cognitive mechanisms of open vigilance'. He defines 'open vigilance' as being open to the possibility that comprehended claims are true, while also being vigilant against falsehoods. However, ironically, if such cognitive mechanisms exist they'll actually be partly due to, rather than evidence against, our credulity. That is, given that the extreme credulity of Spinozan belief formation is logically unavoidable, but biologically costly, it creates an evolutionary pressure towards developing cognitive mechanisms that can somewhat counteract it.

Oddly, Mercier doesn't mention Spinoza's role in the origin of the idea that merely comprehending a claim involves believing it, despite the relevance of this idea to the subject of his book, and even though he cites Gilbert's paper, which does mention Spinoza's role. The fact that Mercier didn't think that it was worth mentioning such a basic fact about the history of this idea is possibly another illustration of the idea's current low status.

A second problem with Gilbert's argument is that there's currently no theoretical basis, or evidence, for the idea that our cognitive faculty evolved from our perceptual faculty. And a third problem is that a belief is a cognitive state, and so the idea that perception is 'quintessentially Spinozan' – that to perceive something is to believe it – actually contradicts the idea that our cognitive faculty came after our perceptual faculty.

A fourth problem with Gilbert’s argument is that if to perceive something is to believe it, then, as Gilbert states, such beliefs form before we’ve had a chance to reason about the content of the perception. As I explained in chapter 3, the formation of beliefs about the nature of, and events in, our surroundings via perception must involve at least some reasoning about the content of our perceptions – although, given the speediness of the brain, such reasoning is often so basic, and therefore brief, that such beliefs can seem to be a direct product of the perceptual process. So the starting point of Gilbert's argument, that perception is Spinozan, is false.

So Gilbert's alternative theoretical argument fails to vindicate Spinoza's theory in relation to our comprehension of claims, in addition to not addressing the entrance of claims into our mind via reasoning, imagination and recollection.

The argument that I present in this chapter, which does vindicate Spinoza's theory, is the only other alternative theoretical argument that I'm aware of. The essence of the argument is surprisingly simple, considering its counterintuitive conclusion, and can be presented in just nine steps:

    1. There are two, and only two, logically possible ways that the content of a claim, X, can exist in our mind: as the content of X and as part of reality.

    2. The former involves thinking about X.

    3. And thinking about X is different from thinking X.

    4. Therefore thinking X must involve the content of X existing in our mind as part of reality – that is, thinking X always involves believing X.

    5. If X exists in our mind then we must be either thinking X or thinking about X, given that there’s no other possibility.

    6. Therefore the entrance of X into our mind, whether via reasoning, comprehension, recollection or imagination, must consist of us either thinking X or thinking about X.

    7. However, the entrance of X into our mind is the outputting of X from a mental process, whereas thinking about X is the processing of X by a subsequent mental process.

    8. But the thought X is the output of a mental process.

    9. Therefore the mere entrance of X into our mind, whether via reasoning, comprehension, recollection or imagination, causes us to believe X.

As I explained in chapter 1, the past absence of a good theoretical argument for this theory is ultimately much more an effect than a cause of the poor status of the theory within academia. That is, the more fundamental cause of its poor status is the combination of its counterintuitive nature and insufficient open-mindedness within academia. This has led most academics who’ve encountered it to not take it seriously, which has in turn resulted in academia not giving it sufficient attention to develop a good argument for it.

It's over 340 years since Spinoza published his theory. Such a long gap between the creation of a theory and its vindication is unusual in science, although that gap was even greater, much greater, for the theory that Earth goes around the Sun – heliocentrismrather than vice versageocentrism. The ancient-Greek astronomer Aristarchus of Samos presented the earliest known heliocentric theory. But acceptance of heliocentrism only began, and very slowly, eighteen centuries later, after the publication in 1543 of the book On the Revolutions of the Heavenly Spheres, by the mathematician and astronomer Nicolaus Copernicus. The book presented a mathematical model of heliocentrism that was reasonably compatible with the motions in the sky of the Sun, the Moon, the observable planets, and the stars. Acceptance of heliocentrism accelerated in the 17th century after this mathematical model was improved by the mathematician and astronomer Johannes Kepler, and because astronomical observations by the scientist Galileo Galilei, using the newly-invented telescope, supported heliocentrism over geocentrism.

Left: the title page of the first edition of Copernicus's On the Revolutions of the Heavenly Spheres, which was written in Latin.

Right: a page of the book with a diagram of heliocentrism.

The paragraph on the title page is the book's blurb, which ends 'buy, read, and enjoy'.

Copernicus's use of mathematics to reach a conclusion about nature, rather than merely using mathematics to describe the current understanding of nature, was controversial. Even by Galileo's time a professor wrote that '... anyone who thinks that he can prove natural properties with mathematical argument is simply demented... ' (source, chapter 5). However, this approach eventually became accepted as a legitimate means of furthering our understanding of nature. Today, the application of mathematics to develop and refine theories in physics is a whole branch of physics – theoretical physics – and is fundamental to cosmology.

In the field of psychology today, using logic alone to reach conclusions about human psychology is considered unscientific, given the absence of observational evidence in such reasoning. However, the logical necessity of credulism and the certainty of belief means that these aspects of human psychology can only be explained by logic – and likewise for their profound implications for human psychology. Therefore using logic alone to reach conclusions about human psychology needs to become accepted as a legitimate means of furthering our understanding of human psychology, as happened with using mathematics to further physics and cosmology.

As I mentioned in chapter 1, although heliocentrism initially seemed obviously contrary to experience, closer analysis revealed that it isn't. Likewise, as I've shown in this chapter and the previous, although credulism and the certainty of belief can initially seem obviously contrary to experience, closer analysis reveals that they aren't. Hopefully this fact, and the theoretical arguments that I've presented, will lead to these two theories being taken seriously by academia today, rather than after a few more centuries.

Also, a revolutionary theory provides researchers the opportunity to make relatively easy but significant further discoveries by working through the implications of the new understanding. And the sooner a researcher begins this work the more such low-hanging fruit is potentially available to them. So hopefully this potential reward for open-mindedness towards these two theories about the psychology of belief will also contribute to them being taken seriously by academia today.

The next chapter is in progress...

Share book on Twitter

Discuss book on Reddit

Receive updates:

To receive updates about new content on this site, submit your email address via Substack – you don't need a Substack account.

Feedback:

I welcome feedback about both my writing and its content, whether via Reddit or derrick@derrickfarnell.site.

Support my independent research and writing



This book is continually evolving: new chapters will continually be added, and the content, titles and order of chapters can change. Referencing of this book should therefore state the date of reading. Also, you can save the current version of this chapter in the Internet Archive, and then link to the archived copy.