Physicalism And Conceivability: Reply To David Pallmann

In a recent facebook post, David Pallman provided the following argument against mind-body physicalism:

“ A modal argument against mind/body physicalism.

1. According to physicalism, I am a physical object/entity.

2. Physical objects/entities cannot possibly exist in the absence of physical things.

3. But I can possibly exist in the absence of physical things.

4. Therefore, I am not a physical object/entity.

5. Therefore, physicalism is false.”

As a reply, I think the physicalist’s best option is to reject premise three by undermining the inference from conceivability to possibility that supports it. In defense of this move, they should, first, provide counterexamples to the claim that positive conceivability entails metaphysical possibility. Second, they should use these examples to motivate an account of conceivability and modal error. Finally, they should argue that, on the basis of this account, anti-physicalist conceivability cases are susceptible to modal error and, thus, unreliable as a guide to metaphysical possibility. Here’s a rough sketch of how that sort of argument might go:

There are possible cases where certain metaphysically impossible situations seem conceivable even after ideal rational reflection. For example, the existence and non-existence of a metaphysically necessary being both seem positively conceivable. However, since one of these cases is metaphysically impossible, at least one metaphysically impossible scenario is positively conceivable. Additionally, it seems positively conceivable that water is composed of H20. However, it is epistemically possible that, in the future, we might discover that we were mistaken and water is actually composed of XYZ. In this situation, what seemed to be positively conceivable (apparently possible, given our knowledge, after ideal rational reflection), would turn out to be metaphysically impossible. This is another possible case where positive conceivability would not be a reliable guide to metaphysical possibility. 

What should we say about conceivability in light of these cases? First, we should give some account of what conceiving of some possibility involves. In my view, the best thing to say is something like this: When we conceive of a possibility, we are describing a total situation in which our worldly evidence is such that we are disposed to judge that certain concepts apply. For instance, when I conceive of a world where water is composed of H20, I describe a world where things with certain functional roles (H20 molecules) realize watery stuff. I am disposed to judge that such a world is one where water is composed of H20, so I take such a world to be possible. However, if I later discovered that water is, in fact, composed of XYZ, then describing such a world (the H20 world) would no longer dispose me to judge that it is one where water is composed of H20. This is because, based on my a posteriori discovery, I would no longer take the relevant worldly evidence (watery stuff) to be actual water. 

The above account suffices as an explanation of why an inference to metaphysical possibility based on conceivability might be defeated by subsequent a posteriori discoveries. However, there are other cases, such as the conceivability of God’s existence and non-existence, that don’t seem capable of being explained in this way. Even if we make the a posteriori discovery that God exists, it seems like we will still be able to describe a total situation in which our worldly evidence disposes us to judge that it is a situation where God does not exist. What these cases show us is that we can describe total situations that, despite being coherent, are nevertheless metaphysically impossible. I think this suggests that positive conceivability is, even in the ideal case, not an indefeasible guide to metaphysical possibility. One lesson we should draw from this is that our judgements about metaphysical possibility cannot be based on conceivability alone. Rather, they must also be informed by the metaphysical implications of a posteriori discoveries as well. 

In light of these considerations, I think what the physicalist should say about anti-physicalist conceivability arguments is that they involve descriptions of coherent total situations containing worldly evidence that dispose us to judge that they are worlds where certain mental phenomena are present in the absence of associated physical phenomena or vice versa. They are ideal cases in the sense that they are not susceptible to defeat by future empirical discoveries because, unlike the case of water and H20, the worldly evidence that disposes us to judge that mentality is present/absent is the existence of mentality itself. When we judge that pain is present, for example, we judge this on the basis of the existence of pain. This is unlike water, where we judge that water is present on the basis of the existence of watery stuff. That is why, even if someone believes that pain is identical to C-fibers firing, they will still find it positively conceivable that pain can exist in the absence of C-fibers. They still find it conceivable because they can describe a total situation where C-fibers are absent but painful sensations are present and, since painful sensations are sufficient for the presence of pain, they will be disposed to judge that this is a world where pain is present but c-fibers are absent. Furthermore, there is no incoherence in our description of a world where pain is present in the absence of C-fibers firing because there are no a priori connections between our concepts of pain (or painful sensations) and C-fibers. As far as a priori reflection is concerned, such a situation is entirely coherent. Nevertheless, based on our a posteriori evidence, the physicalist should say that these concepts both refer to the very same physical phenomenon. Consequently, they should say that the conceivability of anti-physicalist scenarios is not a reliable guide to metaphysical possibility. 

The physicalist can explain the positive conceivability of anti-physicalist scenarios by pointing out that our metal concepts are distinctively “first-personal” in the following sense: We apply them directly on the basis of the phenomena that they refer to. By contrast, our physical concepts are “third-personal” in the sense that we apply them indirectly on the basis of observational evidence. Because these concepts do not have any a priori connections to one another, we cannot infer, a priori, that they co-refer. The possibility of possessing these sorts of co-referring concepts that lack a priori connections can be explained in physicalist terms by appealing to the difference in worldly evidence that disposes us to apply those concepts: We recognize things with certain causal-structural roles as c-fibers and certain phenomenal states of our direct acquaintance as pain. This allows the physicalist to dismiss the positive conceivability of anti-physicalist scenarios an unreliable guide to metaphysical possibility on the grounds that they involve metaphysically impossible descriptions that aren’t recognizable as metaphysically impossible, even after ideal rational reflection. In this sense, they are like the cases where we conceive of the existence and non-existence of God. Anti-physicalist conceivability cases, however, are explained by appealing to the difference in our first-personal and third-personal concepts. 

In summary, the physicalist can provide examples where positive conceivability does not entail metaphysical possibility. These are situations where we describe coherent total situations involving worldly evidence that disposes us to judge that certain facts obtain, even though those situations are metaphysically impossible. The physicalist can then establish that anti-physicalist scenarios depend on descriptions involving worldly evidence that are not a priori incoherent because they appeal to first-personal and third personal concepts that have no a priori connections to one another. Because our a posteriori evidence suggests that mental concepts and physical concepts do, in fact, co-refer, we should conclude that the anti-physicalist scenarios are positively conceivable but metaphysically impossible.  

Addendum: Another lesson that we can draw from these remarks is that conceivability is not the essential tool of metaphysical inquiry that some take it to be. Our modal judgements about metaphysical possibility are determined by more holistic considerations involving a priori reflection, a posteriori discoveries, and abductive theorizing

A Summary Of "Being And Being Known" by Wilfred Sellars

1. Sellars aims to defend the claim that there is an isomorphism between the knower and what is known while disputing the Thomistic understanding of this doctrine. 

2. According to Sellars, this examination is important because many central Thomistic contentions, such as their belief in the immateriality of the intellect, are based upon their understanding of this isomorphism.

3. He begins his explication of the Thomistic doctrine by contrasting it with the account of intellectual acts found in Descartes and the account found in early stages of contemporary British and American realism.

4. According to Sellars, these latter views are united by the idea that intellectual acts are distinguished in terms of what they are related to, rather than in terms of their intrinsic character as intellectual acts.

5. Sellars suggests that this idea leads to unacceptable philosophical consequences. His preferred alternative is to hold that the intrinsic characters of intellectual acts differ in ways that systematically correspond to differences in what those acts are about. The most serious doctrine of this sort, he claims, is the “doctrine of the mental word”.

6. According to the Thomistic doctrine of the mental word, Sellars claims, a mental word is a nature or form that informs the intellect in a way the enables that intellect to think particular thoughts that are about that nature or form.

7. Since, according to Sellars, we are tempted to say that the intellect does not take on the form that informs it in the same way that material objects do, we are led to conclude that the nature or form is informing the intellect in the “immaterial mode”. 

8. Sellars’s Thomist holds that a nature or form can inform the intellect only because it initially informs their sensory faculties in the immaterial mode. The former sort of informing is grounded upon the latter sort. Thus, he says that we can speak of the sensible as well as the mental word. 

9. Sellars holds that the Thomistic conception of intellectual abstraction depends upon their claim that our sensory faculties exhibit an independent form of intentionality that can serve as a basis for the emergence of intellectual intentionality.

10. In contrast to the Thomist, Sellars argues that we can formulate an alternative account of sensory forms that is not committed to the idea that sensory faculties are informed in the immaterial mode. According to this alternative account, sensory experiences involve specific forms in a “derivative sense” that can be analyzed in terms of certain causal relations between types of sensations and types of external objects.

11. Sellars highlights the contrast between the views under consideration as follows: According to the Thomist, material objects and sensations involve the same form in distinct (material or immaterial) modes. According to Sellars, material objects and sensations involve different forms that are specified by different senses of the same word. 

12. On Sellars’s alternative proposal, there is a structural isomorphism between the types of external objects specified by words used in one sense and the types of sensations specified by those words used in another, derivative sense. 

13. Sellars does not focus on arguing for his alternative view of the isomorphism between nature and sensations. Rather, he simply adds that his alternative view entails that the abstractive theory of mental word acquisition is false and that abstractive theories face other difficulties relating to other logical mental words as well (these difficulties can be viewed as a reason to accept Sellars’s view of the isomorphism rather than the Thomist’s).

14. On Sellars’s account, the isomorphism between nature and the senses is a structural isomorphism between external causes and sensory acts that requires no appeal to the possibility of external objects and sensations being informed by a common form in distinct modes. In light of this thesis, he now proposes to argue that there is a similar isomorphism between thought and the world. Furthermore, he holds that this isomorphism between thought and the world is a necessary condition for mental intentionality.

15. Sellars argues that mental words can be understood as “words” in a novel sense that is derived from the sense that applies to linguistic tokens. Like linguistic tokens, he argues, there is a structural isomorphism between specific mental words and specific objects in reality that is determined by a causal relationship between them. This is the isomorphism that he claims is necessary for mental intentionality. 

16. Sellars views claims about the isomorphism between mental words and objects in reality as statements that relate certain tokens, considered as meaningless, to other objects in the external world. By contrast, Sellars views claims about intentional significance as statements that relate certain tokens, considered as meaningful, to tokens of our own language (and other languages) in terms of their role within their own “language”. 

17. By formulating an account of these two sorts of isomorphism, Sellars aims to explain mental intentionality in a way that 1. Doesn’t require mental words that are related to absolute natures by being informed in an immaterial mode, and 2. accounts for how our mental words are related to mind-independent reality.

Thinking And Being: Key Terms

I am trying to compile a list of the key terms (along with their explanations) found in Irad Kimhi's Thinking And Being. The current list can be found here.

Section 293 Of Philosophical Investigations

In section 293 of Philosophical Investigations, Wittgenstein considers the idea that human subjects only know the meaning of the word “pain” on the basis of their own experiences of pain. The passage runs as follows:

293. If I say of myself that it is only from my own case that I know what the word "pain" means—must I not say the same of other people too? And how can I generalize the one case so irresponsibly? Now someone tells me that he knows what pain is only from his own case!——Suppose everyone had a box with something in it: we call it a "beetle". No one can look into anyone else's box, and everyone says he knows what a beetle is only by looking at his beetle.—Here it would be quite possible for everyone to have something different in his box. One might even imagine such a thing constantly changing.—But suppose the word "beetle" had a use in these people's language?—If so it would not be used as the name of a thing. The thing in the box has no place in the language-game at all; not even as a something: for the box might even be empty.—No, one can 'divide through' by the thing in the box; it cancels out, whatever it is. That is to say: if we construe the grammar of the expression of sensation on the model of 'object and designation' the object drops out of consideration as irrelevant.

It may be tempting to interpret the upshot of Wittgenstein’s remarks here in the following way: In order to successfully use a name to refer to some object, that object must be related to the way our linguistic community uses the relevant name. However, in the imagined scenario, since the specific object in each speaker's box is not relevant to their use of the term ‘beetle”, they are not using the word “beetle” as a name for the private objects in their boxes. Likewise, private sensations are not related to the way our linguistic community uses the word “pain” so it does not name private objects that each of us experiences. 

This interpretation might appear to highlight an important continuity between the early Wittgenstein and his later work. In the Tractatus Logico-Philosophicus, Wittgenstein seems to present conditions for meaningful speech about reality. He then seems to show that these conditions cannot be satisfied by speech about language, ethics, and the self, among other philosophical subjects. This interpretation places the reader in a paradoxical situation: In order to recognize that one cannot meaningfully speak about language, ethics, and the self, one must first know that the nature of language does not allow for such speech. But this would seem to imply that Wittgenstein’s speech about language is meaningful after all. The solution, according to some interpreters of Wittgenstein, involves recognizing that, although Wittgenstein’s propositions in the Tractatus are, strictly speaking, nonsensical, they nevertheless make us aware of important ineffable truths about the nature of language. 

If one accepts this interpretation of the early Wittgenstein, section 293 of Philosophical Investigations can be understood as a new application of the old philosophical method. Wittgenstein presents certain conditions that must be met by meaningful speech and shows that speech about private objects does not meet those conditions. However, on this view, the fact that the conditions for meaningfulness cannot be satisfied by our speech about private objects does not imply that there are no private objects in experience. Like the truths of the Tractatus that render us silent regarding that which cannot be spoken about, these truths about experience may simply be ineffable. 

In my view, this general approach is mistaken as an interpretation of the early, as well as the later, Wittgenstein. What Wittgenstein seeks to show us, in Philosophical Investigations, is not that conditions on meaningful speech prevent us from speaking about private objects that may or may not be present. Rather, his remarksp are intended to highlight the fact that we do not use the term “pain” as the name for an object at all. At no point in his remarks does the later Wittgenstein concern himself with how we must speak or what we must speak about in order to speak meaningfully. Rather, in all cases, he simply aims to describe how we do, in fact, use our words. 

Returning to the imagined community of section 293, what this scenario presents is a situation in which a group of speakers do not use the term “beetle” as a name for the object in their box. What it does not present is a situation in which a group of speakers are confronted with private objects that cannot be named. Suppose that each speaker’s box did, in fact, contain a beetle. We can easily imagine a scenario in which a group of speakers opened each other’s box, examined the sort of thing that was inside each of them, and collectively decided to use the word “beetle” as a name for things of that sort. The fact that they do not do this in Wittgenstein’s scenario only shows that the use of the term “beetle” in his example is not what we would call the use of a name. Furthermore, in recognizing that their term “beetle” does not name objects inside of their boxes, we are not thereby committed to claiming that the objects in their boxes cannot be named. 

In a similar fashion, what Wittgenstein’s example shows is that our use of the term “pain” is not the use of a name for an object. What we call a “use of a name” is a use of a word that is responsive to the sort of thing we are naming and how things stand with respect to it. But, as Wittgenstein shows in 293 and the surrounding sections of Philosophical Investigations, this is not how we use the term “pain”. By reflecting on our use of the term “pain”, Wittgenstein aims to show us that it is not the use of name and that, on the basis of similar considerations, it is unclear what the claim “...it is only from my own case that I know what the word "pain" means.” is actually supposed to mean. 

It is crucial to emphasize that Wittgenstein’s remarks in section 293 do not represent a move towards any form of behaviorism or eliminativism about mentality. As he goes on to note in section 304, he believes that there could hardly be a “greater difference” between pain and pain-behavior. Furthermore, he claims that “[Pain] is not a something, but not a nothing either!”. To claim that mentality is nothing other than behavior would be to hold that pain is, in fact, something that exists. But Wittgenstein’s latter remark is intended to highlight the fact that claiming some X does or does not exist only happens within a certain sort of language game. Specifically, it only happens in a language game that involves using a name for the relevant object. By denying that pain is a something or a nothing, Wittgenstein is simply pointing out that such affirmations have no role that is connected to our actual use of the word “pain”. For Wittgenstein, behaviourist and eliminativist theses depend upon the same misunderstandings that so-called “realism” exhibits. 

In conclusion, I would like to make some brief remarks on Wittgenstein’s diagnosis of the error that is highlighted by section 293 and discuss its relation to his early work. In section 125 of Philosophical Investigations, Wittgenstein describes the “fundamental fact” that gives rise to a need for philosophical reflection. This fact, he claims, is that “... we lay down rules, a technique, for a game, and that then when we follow the rules, things do not turn out as we had assumed.” He goes on to say that “...we can avoid ineptness or emptiness in our assertions only by presenting the model [of a language game] as what it is, as an object of comparison—as, so to speak, a measuring-rod; not as a preconceived idea to which reality must correspond.” (S.131). This temptation to understand our use of language in terms of a preconceived model is what Wittgenstein calls “dogmatism” in philosophy.

The error that Wittgenstein highlights in section 293 is one form of philosophical dogmatism. Specifically, it is a commitment to the preconceived notion that our use of the term “pain” can be understood “on the model of 'object and designation'”. (S.293) Wittgenstein believes that this error can be overcome once “we make a radical break with the idea that language always functions in one way, always serves the same purpose: to convey thoughts—which may be about houses, pains, good and evil, or anything else you please.” (S.304) In other words, once we recognize that the word “pain” is not necessarily used to try and designate a certain object, we can overcome our tendency to think that pain must be a something or a nothing. 

The recognition that causes that philosophical puzzle to disappear also dissolves the apparent paradox at the heart of the Tractatus. The interpretation of the Tractatus considered earlier claims that Wittgenstein presents a theory of meaning and language that implies that his own propositions are nonsensical. This seems to suggest that, if his book succeeds, he must be using nonsensical propositions to make the reader aware of ineffable truths. However, if we follow the later Wittgenstein’s rejection of dogmatism, we can recognize that language is not always used to describe facts about reality. Rather, as Wittgenstein notes in section 295, philosophy provides “A full-blown pictorial representation of our grammar. Not facts; but as it were illustrated turns of speech.” To understand this passage is to understand that philosophical propositions can serve a purpose that does not involve conveying truths of any sort. They do not need to involve any attempt to speak where we must remain silent. In my view, this was already understood by the early Wittgenstein when he insisted that his nonsensical propositions were nevertheless “elucidatory.” Insofar as he later came to view his own efforts in the Tractatus dogmatic, the relevant form of dogmatism must be located elsewhere.

The Search For A Logical Robot: Critical Remarks On Artificial Intelligence

The recent history of technological development has raised significant questions regarding the future possibility of genuine artificial intelligence. Specifically, many scientists and philosophers (along with the general public) have become increasingly convinced that it will someday be possible to use technological innovations in order to construct a being capable of thinking and reasoning in the same ways that human beings do. In addition to the popular worries that this has raised concerning the practical risks and metaphysical implications that such a being would present, these speculations have also led many to reflect on how such a being could be identified, were one to emerge. 

These reflections have received further encouragement from the advent of large language models such as ChatGPT, which emulate human speech patterns with an astonishing degree of accuracy. Indeed, some computer scientists have already been fully persuaded that ChatGPT is a genuine rational subject that deserves to be treated as such. However, to what extent are these convictions justified? In order to answer this question, we must first investigate what the appropriate criteria for identifying the emergence of genuine artificial intelligence could possibly be. The success of this investigation, in turn, will depend on a proper conception of intelligence as such.

In a recent article, Jensen Suther surveys contemporary philosophical thought on artificial intelligence and highlights several plausible requirements that any intelligent being must satisfy. One of these requirements, famously defended by Hubert Dreyfus, holds that any genuine intelligence must be embodied. When we think about genuinely intelligent behavior, one of its core elements involves an ability to modify one’s behavior in light of success or failure. If a being has no capacity to receive data, act in light of that data, and adjust its behavior in light of the results of their activity, then in what sense can it be said to be reasoning at all? If we accept that this capacity for informed behavioral modification is a real requirement for intelligence, there are two important implications: First, any genuinely intelligent being must have some sort of body capable of behaving in certain ways and having that behavior modified in light of incoming data. Second, that being must have some determinate goal that informs how it modifies its behavior in light of incoming data. In the absence of some goal, there would be nothing to guide its behavioral modification and, consequently, no basis for distinguishing intelligent behavioral modification from unintelligent modification, so this latter feature is just as necessary as the former. Together, we can call them “the embodiment criterion”. 

However, even if we accept the embodiment criterion for genuine intelligence, there is another key feature which any intelligent being must possess: Intelligent beings, by thinking, must be capable of determining their own activity as embodied beings. We can call this the “self-determination criterion”. On the face of it, this criterion seems straightforward enough. By thinking and reasoning, intelligent creatures can decide what they should do in light of what is the case and act accordingly. However, in what sense can an agent be genuinely self-determining if it cannot determine the principles that govern its own acts of thinking and reasoning? If an artificial being is pre-programmed with rules for thinking or methods for forming such rules, then its own “rational” procedures are determined by a source that is wholly external to it. If it is not pre-programmed with rules or rule-forming methods, then it is hard to see how it can be said to have rule-governed behavior at all. In the former case, it seems like the agent is governed by external constraints in a way that is incompatible with genuine intelligence. In the latter case, it seems unconstrained in a way that is also incompatible. 

For human beings, a solution to this dilemma is possible: When human beings think, they also place themselves under a shared set of rules that characterize the thoughts of the intellectual community that they are a part of. By taking on the responsibility to think in accordance with these rules, these rules govern their particular acts of thinking without being pre-programmed in them by any external source. To the extent that the rules governing human thinking are established by a community, human thinking can be said to be a socially constituted phenomenon that is self-imposed by individual thinkers. Furthermore, human thinkers remain genuinely self-determining insofar as they collectively shape the public rules that govern them by reasoning with one another. 

However, this solution to the dilemma posed by self-determination is not obviously available in the case of artificial intelligence. The reason why human beings can defer to socially instituted rules of thought is because human beings recognize one another as potential thinkers that they can treat as rule-governed subjects. It is because they are recognized as potential thinkers that it is possible for them to place themselves under the rules of their intellectual community and be held responsible for them. But in the case of AI, this potential for intelligence is precisely what is at issue. Insofar as their potential for intelligence is not recognized, they will not be recognized as potentially rule-governed subjects. Consequently, they will not be able to place themselves under the rules that govern our intellectual community and thereby satisfy the self-determination criterion. 

The moral of the above considerations is as follows: The possibility of genuine intelligence requires a being to be an embodied member of an intellectual community that recognizes them as a potential thinker. This is the only way that an agent can satisfy the embodiment criterion as well as the self-determination criterion. Human beings recognize other human beings as potential thinkers because they recognize themselves as intelligent creatures of the same sort. They recognize each other as deferring to public rules because they understand what cases of deference look like for creatures of the sort that they are. However, this recognition does not extend to non-human agents. We cannot treat such beings as potential thinkers because we do not know whether and when they are capable of deferring to public rules. In order to know that, we would have to know something about the nature of their life form. But artificial agents have no life form to know about. They are not alive. 

Recent developments in technology have given rise to two questions: Is genuine artificial intelligence possible and, if so, can we identify when it is present? As this discussion suggests, it is a mistake to view these questions as separate from one another. The possibility of genuine artificial intelligence depends upon the ability of humans, or some other rational creatures, to recognize when it is present. This is the only way for artificial intelligence to satisfy the self-determination criterion. It is not possible for artificial intelligence to be identified in this way because it bears no recognizable form of life. If the search for a logical robot is to reach its conclusion, it cannot simply involve the production of artificial intelligence alone. Rather, as Jensen Suther notes, “we can’t produce artificial intelligence without also producing artificial life.”

"Hegel Against The Machines" by Jensen Suther: https://www.newstatesman.com/ideas/2023/07/hegel-against-machines-ai-philosophy?mibextid=Zxz2cZ

How Is A Priori Knowledge Possible? An Argument For Absolute Idealism

 [This post is a sequel to my previous post, “On The Immateriality Of Mind”]

What is a priori knowledge and how can we possibly attain it? In order to answer these questions, we must first reflect on knowledge and its conditions more generally. At a minimum, if I (or any rational subject) knows something, we believe what we know truly on an appropriate basis. However, is this all that is required? Many philosophers have objected to this proposal as an account of the sufficient conditions for knowledge on the grounds that there are clear cases where true beliefs formed on an appropriate basis still fail to qualify as genuine knowledge (these are the famous “gettier cases” and their variants). I would like to set these cases aside for the moment. Regardless of how they are ultimately addressed, there is a further puzzle facing any account of the possibility of genuine knowledge. Namely, even if we did have a sufficient basis for knowledge available to us, would this alone be sufficient for us to be in a position to form true beliefs on that basis?

It seems to me that a sufficient basis of this sort would not be enough for us to understand how it is possible for us to form true beliefs. In order for me to form a belief on some basis, I cannot simply be aware of that basis. Rather, I must also recognize that my belief is formed upon a basis that is sufficient for genuine knowledge. If I lack this awareness then, for all that I am reflectively aware of, my basis may, in fact, be insufficient. In other words, in forming my belief upon that basis, I would still not be able to satisfy myself that my belief is, in fact, true. For all that I am reflectively aware of in forming my belief that P, it is nevertheless open to me that, possibly, P is not the case. But if I am in a position where I can entertain the possibility that P is not the case, given all that I am reflectively aware of, then I do not genuinely believe it at all. To believe that P is to hold that P is what is actually the case, and to arrive at such a belief with the aim of thinking what is true, I must recognize some basis which I take to be capable of settling the question, “P or not-P?” 

Insofar as I take the reasons that explain my belief to be what settles the question, “P or not-P?” I must think that the truth of my belief is ensured by the reasons that lead me to form my belief. In other words, if I form my belief upon some basis, I cannot then proceed to investigate whether or not my basis for forming that belief is sufficient for ensuring its truth. If I believe that P, I must, in forming that belief, already be satisfied that my basis for believing is sufficient. This raises a question: How can we have knowledge that the causes of our beliefs is sufficient for knowledge unless we already possess some sort of knowledge about thinking and its proper explanation in the first place? On the one hand, if we say that we do not possess such knowledge, then it seems that we must admit the possibility of beliefs that are formed in the absence of an awareness that those beliefs have a sufficient basis for knowledge. On the other hand, if we maintain that we do possess such knowledge, then, on pain of circularity, it would seem that this knowledge cannot depend on our awareness of any sufficient basis at all. Solving this puzzle is what requires us to account for the possibility of a priori knowledge. It requires us to account for the possibility of satisfying ourselves of the truth of our beliefs without being aware of any sufficient basis for forming them.

If I believe that Socrates is a mortal because of the facts that all men are mortal and that Socrates is a man, then I recognize my reasons for belief as a sufficient basis for my belief that Socrates is a mortal. This requires me to know that my beliefs, when they are explained by certain reasons, are explained by reasons that ensure the truth of my beliefs. If I did not already know this, then it would remain open for me to doubt whether my reasons for believing that Socrates is a mortal were, in fact, good reasons for believing that. In this case, all that was reflectively available to me would not enable me to settle the questions “Is it the case that Socrates is a mortal?” But I am able to settle that question when I form that belief for those reasons because I do know that my beliefs are explained by reasons that ensure the truth of what I believe. In other words, I know that judgment is a certain sort of power that, when exercised, produces knowledge. I know that judgment is a power of knowledge.

However, as noted previously, we must still account for my knowledge of this very power. How can I know that judgment is a power of knowledge if this knowledge is already presupposed whenever I form beliefs on the basis of reasons? If it is required in order for me to form beliefs on the basis of reasons in the first place, then this knowledge cannot itself depend upon any reasons for belief. Rather, it must be a priori. How then, can I take what I believe, in knowing that judgment is a power of knowledge, to be true? 

When we believe on the basis of good reasons, we take the basis of our beliefs to ensure the truth of those beliefs. If we believe something without any such basis, in order to be satisfied that our beliefs are true, we must be in a position to recognize their truth in the absence of any basis. In other words, we must be satisfied that their truth is ensured in the absence of any basis apart from our believing them. When we believe that judgment is a power of knowledge, this belief cannot depend on anything other than the activity of thinking itself. If it did, then it would remain open that, despite believing that judgment is a power of knowledge, my belief might nevertheless be false. In order for this knowledge to be a priori, I must know that the truth of my belief does not depend on anything other than my activity of thinking alone. I must know that thinking itself ensures the reality of the power that it is and, consequently, can know itself to be such a power in the absence of any independent basis for forming such a belief. 

This is how it must be with a priori knowledge in general. In order to know something, independently of any basis, I must know that the activity of thinking itself ensures the reality of what it knows, a priori. Insofar as a knowledge of the nature of thought, as a power of judgment, must be a priori, we must know that the reality of that nature is ensured by the activity of thinking itself. In this sense, we can say along with Jean-Paul Sartre that, with respect to thinking, essence does not precede existence. However, we must oppose Sartre when he says that existence precedes essence. The nature of thought and its activity do not stand in any relation of priority with respect to one another. Rather, the essence of thinking is one and the same as its activity. 

The reality of our a priori knowledge of the nature of thought establishes that thinking alone ensures the truth of what it thinks about its own nature. However, our a priori knowledge is not limited (and cannot be limited) to the nature of thought as such. Our a priori knowledge also includes the principles that govern reality in its entirety. In other words, we possess a priori knowledge of the laws of logic. Insofar as we know, a priori, that any fact opposes the negation of that fact (the law of non-contradiction) and that, for any possible fact, it either obtains or does not obtain (the law of excluded middle), the laws of logic are known independently of any mind-independent basis. Following the remarks made above, this entails that the reality of these laws must be known to be ensured by the activity of thinking alone. In other words, the nature of Being, along with the nature of Thought, must be known to be ensured by the activity of thinking alone. Indeed, just like the nature of thought, the nature of Being must be one and the same as the activity of thinking.

The conclusion specified in the final remarks of the preceding paragraph can be formulated in another way: Thinking and Being are the same. This is the formula of Absolute Idealism. This sameness is known, a priori, in any judgment, insofar as a thinker is satisfied that their judgment is true. Insofar as we make judgments on the basis of reasons, these judgments depend on a priori knowledge that does not, and is known not to, require any such basis. The truth of this knowledge must be known to be ensured independently of anything apart from the activity of thinking itself. Insofar as our a priori knowledge is a knowledge of the nature of Thought (the principles of thinking) and the nature of Being (the principles of logic), we must know that the reality of these natures is nothing apart from the reality of the very same activity. 

The ancient philosopher, Parmenides, famously wrote that “It is the same thing that can be and that can be thought”. Aristotle followed his insight by treating the metaphysical principle of non-contradiction as one and the same as the psychological principle of non-contradiction (Metaphysics, 4.3). These philosophers are articulating their knowledge that the activity of thinking is the same as the activity of Being. In order for contemporary philosophy to successfully address the myriad of puzzles that it has consistently failed to overcome, this knowledge must ultimately be recovered.

On The Immateriality Of Mind

C.S. Lewis argued that, if we conceive of rationality and judgments as a physical organ and its products, then we cannot consistently hold that any of our beliefs are rationally explained, as opposed to solely being causally explained. 

In reply, some philosophers have suggested that Lewis mistakenly inferred that, if rationality and judgements have a sufficient causal explanation, they must lack a rational explanation. According to these philosophers, Lewis failed to show that rational and causal explanations are incompatible with one another. Insofar as this incompatibility has failed to be established, they conclude, Lewis cannot claim to have shown that naturalism precludes rational explanation.

Can anything be said on Lewis’s behalf? It seems to me that, when we reflect on what a “rational explanation” really amounts to, it can be shown that there is indeed an incompatibility of precisely the sort that Lewis’s argument requires. 

One objection that has been raised against Lewis is the claim that “reasons explanations” are  distinct, non-causal sorts of explanations that are different from, but not incompatible with, causal explanations. On this view, when we provide reasons for our beliefs, we are not appealing to the causes of our beliefs. Rather, we are placing our belief in the “space of reasons”, where it can stand as reasonable or unreasonable depending on the reasons we cite for holding it. If we can have reasons for belief that are distinct from the causes of those beliefs, it would seem that the existence of sufficient physical causes for our beliefs does not stand in the way of our ability to recognize them as justified on the basis of reasons. 

However, the suggestion that reasons provide a special sort of non-causal explanation faces a serious difficulty: If reasons are non-causal in the sense described above, then forming a belief for certain reasons cannot provide any basis for thinking that what we believe is actually true. If I believe that P for some good reason, Q, the truth of my belief will only be guaranteed if Q actually obtains. But if I do not take Q to be what causes my belief that P, then the fact that it is my reason for believing that P does not put me in a position to know whether anything at all ensures the truth of my belief that P. Lewis himself makes a similar point:

“...even if [non-causal] grounds do exist, what have they got to do with the actual occurrence of belief as a psychological event? If it is an event it must be caused. It must in fact be simply one link in a causal chain which stretches back to the beginning and forward to the end of time. How could such a trifle as lack of logical grounds prevent the belief’s occurrence and how could the existence of grounds promote it?” (Lewis 1978, p. 16. Brackets added)

For all I know, Q may be my reason for belief even though, in fact, it is not the case that Q. Consequently, knowing that I believe that P because of some good (non-causal) reason, Q, will not put me in any position to recognize whether my belief is true or false. If reasons are going to serve as explanations that put us in a position to recognize the truth of our beliefs, then they must be facts that cause us to form beliefs as a rational response to what is actually the case. 

In light of the considerations above, we should conclude that “reasons explanations” are some sort of causal explanation. If the mind is a physical organ, then reasons must be causes that affect that physical organ in a way that leads to the production of beliefs. However, this proposal is in tension with the claim that we recognize reasons as what cause our beliefs as well as what ensure their truth. In short, we cannot simultaneously hold that the mind is physical and that our beliefs have genuinely rational explanations. If the mind is a physical organ, then the causal relations that obtain between our beliefs and the facts that cause them are determined by the laws of nature that govern our universe. In other words, when certain facts cause a belief to be formed, this will result from the physical character of those facts, the physical character of the mental organ (along with our beliefs), and the laws of nature that determine how things with those physical characteristics interact with one another. However, if this is the case, then there is no basis for supposing that the same facts that cause my beliefs also ensure their truth. Assuming that the mind is a physical organ, is perfectly coherent to suppose that our beliefs are caused by facts that have no relation at all to the things we form beliefs about. Even if it just so happened that our beliefs were caused by facts that ensured their truth, the mere awareness that our beliefs were caused in a certain way would still not enable us to actually arrive at a judgment concerning their truth. In order to recognize our beliefs as true, there must be some evident and essential connection between the causes of our beliefs and the facts that those beliefs are about. But this connection is precisely what we must reject insofar as we hold to the view that the mind is a physical organ. We must reject it because the causes of physical entities are fully determined by their physical characteristics and the laws of nature, not by the intentional content of our beliefs or principles of logical consequence.

We are now in a position to give a precise account of why rational explanations of belief are incompatible with other forms of causal explanation: In order to have genuinely rational explanations that can establish the truth of the beliefs that they explain, there must be an evident and essential connection between the facts that explain our beliefs and the facts that ensure the reality of whatever our beliefs are about. However, as shown above, if the mind is a physical organ that is susceptible to non-rational forms of causal explanation, then there can be no evident and essential connection of this sort. Consequently, insofar as we take our beliefs to have sufficient non-rational explanations, we cannot also hold that they are rationally explained. 

Since our beliefs do have rational explanations in terms of reasons that ensure their truth, what should we conclude about the nature of the mind? As this discussion suggests, it cannot be any physical organ. Rather, the reality of reason itself establishes the immateriality of mind and judgment. Insofar as the mind is non-physical, it is not governed by physical laws and the causal relations that they entail. The principles of thought are rational principles that guarantee an essential connection between the causes of our beliefs and their truth. We acknowledge the reality of these principles whenever we recognize the truth of our beliefs in light of the reasons that explain them. The implications of this acknowledgement preclude a purely physical account of the mind and vindicate C.S. Lewis’s belief in a “cardinal difficulty” facing naturalism.  

Addendum: 

1. It is sometimes suggested that C.S. Lewis’s argument from reason has been improved upon and/or superseded by more sophisticated attempts to show that naturalism is self-defeating. Specifically, Alvin Plantinga’s evolutionary argument against naturalism has occasionally been held up as such an innovation. Without attempting to refute Plantinga’s argument in detail, it is worth highlighting a key advantage of Lewis’s approach: Plantinga’s argument depends upon a controversial premise concerning the prior probability of reliable cognitive faculties, given naturalism and evolution. By contrast, Lewis requires no such assumption. Even if the prior probability of reliable cognitive faculties was high given naturalism and evolution, Lewis’s argument could still succeed. This is because Lewis attacks the very possibility of rational explanations on naturalism rather than their probability. 

2. The immaterial mind is governed by rational principles that ensure an essential connection between the explanations of our beliefs and their truth. However, there are clearly cases of false belief and beliefs that are not formed for good reasons. How can the possibility of such cases be explained on this account? Although, in normal conditions, the mind will be caused to form true beliefs for good reasons, exceptional cases of malfunctioning remain possible. When someone forms a false belief or forms a belief without good reasons, these must be explained in terms of a non-rational cause. This will involve some sort of interference, where the mind is acted upon by some external, non-rational cause instead of acting in accordance with its own rational principles. This may seem to present a skeptical threat: If we cannot distinguish between cases in which our mind is acting in accordance with rational principles and cases in which it is being interfered with, how can we be confident that our reasons for some belief actually ensure its truth? The general response to arguments from illusion will also apply in this case. Our inability to recognize when we are reasoning unsuccessfully does not entail that we lack conclusive evidence when we are reasoning well. When we are reasoning well, we know that our beliefs are explained by reasons that ensure their truth. Consequently, even though we are unable to recognize when we are reasoning unsuccessfully, beliefs formed by reasoning well are not subject to doubt. 

3. Physicalists may attempt to argue that they can establish a connection between the causes of our beliefs and their truth by appealing to natural selection. Natural selection, they might claim, allows us to account for why our rational faculties successfully track the truth. This may seem to provide grounds for affirming a physicalist account of rational explanation. The difficulty facing any proposal of this sort is simple: These accounts can only explain why our beliefs are generally correlated with the facts that make them true. They do nothing to undermine the key contention that, if the mind is a physical organ, there is no essential connection between the causes and the truth of our beliefs. Furthermore, the absence of this essential connection prevents the physicalist from consistently recognizing the truth of their belief that natural selection favors cognitive reliability in the first place. Because it fails to establish the essential connection required for rational explanation, this evolutionary proposal provides no distinctive advantage for the physicalist.