Nagel’s argument against Davidson in Chapter VI of The View From Nowhere

I. Introduction

Whether we can adequately conceive of every aspect of reality is a deep and perplexing issue which philosophers have traditionally divided into two separate questions. First, the metaphysical question as to the ultimate nature of reality. Second, the semantic and broadly epistemological question of how thought and language are related to the world. The link between these questions is itself a difficult and complex issue that depends upon the particular metaphysical and semantic theories which are adopted. A metaphysical idealist will, for example, consider reality to be essentially dependent upon thought and language. Thus, all existent entities, such as facts, would be necessarily conceivable, since they have no existence independent of thought, making the metaphysical question subordinate to the semantic one. A common-sense realist such as Devitt (1984), on the other hand, might take these two questions to be more or less independent since, for him, the order of dependence is precisely the reverse. On this account, the notion of an inconceivable fact seems perfectly coherent since reality, being independent of thought and language, may outstrip both.

In this essay I will examine an argument by Thomas Nagel from Chapter VI of The View From Nowhere (Nagel 1986; hereinafter vfn) against metaphysical idealism. In particular, Nagel takes issue with a paper by Donald Davidson (1984; hereinafter vics) in which Davidson rejects the notion of a ‘conceptual scheme’ and endorses the intertranslatability of truths between all languages — a thesis that Nagel claims is incompatible with metaphysical realism. I aim to show that Nagel’s argument against Davidson is unwarranted and that the two positions need not come into conflict — or at least not in the way that Nagel appears to think they do. My argument centres upon Nagel’s presupposition that any semantic theory that rules out the existence of inconceivable facts necessarily entails that reality is mind-dependent; i.e. metaphysical idealism. I claim that Nagel’s justification for this presupposition is inadequate as it involves an equivocation concerning the notion of conceivability. In the absence of further independent argument, Nagel’s case for linking the above metaphysical and semantic questions is thereby undermined.

In order to clarify the debate it will first be necessary to define a few key terms. In this, I will follow Devitt in defining realism as the doctrine that ‘the world exists independently of the mental’ (Devitt op. cit: 14). This claim may be further subdivided into the claims that (a) reality is not in any way dependent upon thought and language (the ‘independence dimension’; ibid: 12–15), and (b) that the entities we ordinarily take it to contain — tables, people, electrons, etc.1 — really do exist (the ‘existence dimension’; ibid: 15–21).2 Idealism, on the other hand, rejects (a), since it takes reality to be dependent upon thought to the extent that it is constituted by it, and reinterprets (b) in terms of mind-dependent existence. The idealist thus denies that objects literally exist in the way that the realist supposes they do (Wright 1992: 2). This leaves room for a third position, or anti-realism, which opposes one or both of the realist’s claims, but that does not construe thought as being wholly constitutive of reality, as per the idealist (e.g. Dummett 1978). Despite Nagel’s terminology, I take it that his argument is directed not only at idealism, as defined above, but at any anti-realism that denies the existence of inconceivable facts. Finally, it is necessary to differentiate the notion of ‘reality’ or ‘the world’ from both the phenomenal ‘life-world’3 of human experience and the physical universe studied by the natural sciences. In keeping with the nature of Nagel’s enquiry, I assume that ‘reality’ is an all-encompassing term covering both physical and mental realms, whilst leaving it open as to whether it is to be identified with either (although neither Nagel nor Davidson finds either possibility, i.e. physicalism or immaterialism, plausible).

II. Nagel versus Davidson

Nagel’s argument is directed against the anti-realist view that ‘what there is must possibly be conceivable by us’ (vfn 93). Such a view rules out the existence of facts that are inconceivable by us — perhaps upon the basis that our conception of reality cannot extend beyond those categories of things with which we are already acquainted (vfn 94). Whatever the motivation, the anti-realist denies that there is a gap between what exists, i.e. reality, and what we can conceive of (where the terms ‘we’ and ‘conceive’ have yet to be defined). Nagel, on the other hand, claims that our conception of reality extends beyond not only what we can currently conceive of, but beyond what we could possibly conceive — or as he puts it, ‘beyond the reach of our minds’ (vfn 90). To deny this is, according to Nagel, to accept a form of ‘idealism’ in which the proper order of dependence between mind and world is reversed (vfn 92, 108–9). Although Nagel never explicitly spells out his grounds for making this link between realism and conceivability, it is nevertheless possible to discern them from the body of his argument, which is the approach that I will be taking below.

It is important to note that Nagel does not argue that there are any actual facts that we are unable to grasp, but merely that their existence cannot be ruled out in advance, as the anti-realist attempts to do. Similarly, whilst acknowledging that the dispute concerns the nature of thought, Nagel does not profess to have an alternative account to offer (vfn 95). Rather, he claims only that ‘realism makes as much sense as many other unverifiable statements [that] present fundamental philosophical mysteries to which there is no solution’ (ibid.). In other words, his argument represents a purely negative case against anti-realism, rather than a positive case for realism (although presumably, if the argument is successful, realism will be seen as all the more plausible as a result). Furthermore, since realism is the ‘natural picture’ (vfn 92), the burden of proof is supposed to lie with the anti-realist, who must demonstrate that the notion of an ‘inconceivable fact’ is incoherent if his position is to hold sway (vfn 93). Thus Nagel does not seek to refute anti-realism per se, but merely the claim that the notion of an ‘inconceivable fact’ is incoherent. Despite this, however, Nagel does think it probable that such facts exist, although he is (almost by definition) unable to prove it. He justifies this on the basis of humility (ibid.) and through an analogy that I shall examine in the following section. However, I will first attempt to establish precisely what Nagel takes the connection between inconceivable facts and idealism to be, and how this relates to Davidson’s argument.

The paper by Davidson with which Nagel takes issue is primarily concerned with refuting the notion that truth is relative to a ‘conceptual scheme’, as claimed by Kuhn (1962) and Feyerabend (1962), amongst others. In it, Davidson rejects the idea that we have any grasp of the idea of truth independently of language, and specifically of the notion of translation (vics 16). Even Tarski’s Convention T, which is widely accepted as a minimal condition for truth (although not necessarily as a definition of it), employs a form of translation from an object language to a metalanguage, as in the sentence:

(1)   ‘Snow is white’ iff snow is white.

vics 16

(although, as Devitt [op. cit: 169] points out, even recognising the truth of this seemingly trivial fact already presupposes a great deal of theoretical and linguistic knowledge). On Davidson’s view, the notion of an ‘inconceivable fact’ is incoherent since whatever is inconceivable falls outside the bounds of language, and so the notions of truth and falsity, which are based upon translation, simply do not apply. Conversely, anything that can be stated in one language can, in principle at least, be translated into any other language — or at least anything that we would call ‘language’. Care must be taken to differentiate this thesis from the closely related, but obviously false, claims that (a) there is a word or term for every concept in every language, and (b) that any reasonably competent speaker of the target language could readily understand such a translation. Indeed, it may be incredibly difficult and complex to translate certain sentences between one language and another since the relevant concepts may be lacking and require further detailed explanation. Davidson’s point, however, is that in order to be capable of truth or falsity, a statement must be translatable into some recognisably linguistic form, no matter how simple or complex the resulting translation may turn out to be.

Davidson’s position clearly rules out the existence of inconceivable facts, making him a clear target for Nagel’s argument. It is less clear, however, that it can properly be termed a form of idealism. Firstly, Davidson’s thesis is a primarily semantic one concerning the nature of truth and the distinction between a ‘conceptual scheme’ and its ‘empirical content’ — a distinction he calls the ‘third dogma’ of empiricism (vics 11).4 In rejecting this distinction, Davidson rules out the idea that there is ‘something neutral and common that lies outside all schemes’ (vics 12), such as the raw content of human experience, or some ‘theory-neutral reality’ (vics 17). However, this does not mean to say that he gives up on the notion of empirical content or reality altogether, but merely that these should not be conceived as being relative to a conceptual scheme. Davidson concludes his 1984 paper by saying:

In giving up the dualism of scheme and world, we do not give up the world, but reestablish unmediated touch with the familiar objects whose antics make our sentences and opinions true or false.

vics 20

Thus, far from endorsing a form of idealism, Davidson affirms the mind-independence of ‘familiar objects’, which are sufficiently distinct from our thoughts to play a role in determining their truth or falsity.5 Indeed, his rejection of conceptual relativism arguably places him in a better position to affirm the existence of everyday objects than Nagel, who implicitly endorses this doctrine. Elsewhere, Davidson also asserts the objectivity of both thought, which is grounded in Tarskian truth conditions, and of knowledge, which ‘is of an objective world independent of thought or language’ (Davidson 2001: 138). The relationship between thought, truth and reality is, for Davidson, a complex one in which belief connects truth with meaning, but is not constitutive of reality in the strong sense indicated by the idealist (ibid: 189). It therefore seems incorrect — or at least misguided — to characterise him as a metaphysical idealist.

Based upon the above readings, the disagreement between Nagel and Davidson centres upon the coherence of the notion of an ‘inconceivable fact’, and the nature of language, truth and reality. Thus, Davidson does not so much claim that ‘certain attempts to form significant thoughts [e.g. that there are inconceivable facts] fail’ (vfn 94), but that truth is not a concept that can apply to anything of which we cannot possibly conceive (indeed, the very notion of a ‘thing’ is arguably inapplicable in such contexts). In order to further elucidate the basis for the disagreement, we must therefore examine the notion of ‘conceivability’.

III. Knowledge, Understanding and Conceivability

Much of Nagel’s argument against Davidson is based upon a single analogy in which he envisages a race of beings whose mental abilities are, by stipulation, no greater than those of an average human nine-year old (vfn 95–7). Since adult humans can conceive of things — Maxwell’s equations, the general theory of relativity and Gödel’s theorem are Nagel’s examples — that are beyond the comprehension of such beings, it seems reasonable to assume that the same thing might apply to ourselves with respect to yet more complex or sophisticated facts. Nagel argues that the congenital nine-year olds would therefore be incorrect to claim that reality is limited to what they themselves can conceive of, since this contradicts what we already know to be true, namely that the general theory of relativity et al. exist. By analogy, we (and specifically Davidson) would be wrong to conclude that only what falls within the limits of our own comprehension is real for similar reasons. In this way, Nagel infers that there may be things that are conceivable by beings whose minds are more sophisticated or subtle than our own, but which are nevertheless permanently beyond our limited comprehension — i.e. ‘inconceivable facts’.

Nagel’s analogy raises important questions concerning the nature of conceivability and precisely who it is that such facts are deemed to be conceivable by.  Whilst nobody would deny that there are things that we, either individually or collectively, do not know, it is less clear that Nagel’s analogy addresses the issue of what we could not know. There are, in effect, several different ways in which we might be ignorant of a fact. The limited extent, or finitude, of our (actual) knowledge gives rise to what might be called epistemic ignorance — i.e. not knowing something that we could, were it to be explained to us or made perspicuous by means of a scientific experiment, for example, come to know. Knowledge of certain facts, however, may require the acquisition of new concepts, and it is a characteristic of natural language that concepts may be created, extended and altered in this way, thus helping to overcome what we might call our conceptual ignorance. Nagel’s analogy, however, alludes to an entirely different kind of ignorance, which I will call cognitive inadequacy. This involves the existence of facts and concepts that we (or the race of congenital nine-year olds) are wholly unable to grasp due to our level of intelligence, or the incompatibility of these facts (or the concepts that they employ) with human thought. However, it is arguable that such constraints are not in fact fixed quantities. They may, for example, be overcome from time to time by certain extraordinarily gifted individuals, such as a Maxwell or Einstein, or, in the longer term, through the development of new technologies, techniques, or even through further evolution of the species. We must also take care to distinguish between our practical ability to understand a fact, and its expressibility in a language that we can (or could ever) acquire. There are many facts — Maxwell’s equations, for example — that are incomprehensible to the majority of human adults due to their complexity and the level of background knowledge required in order to understand them fully. This does not, however, make them semantically inexpressible in the sense that Nagel’s analogy seeks to establish, and that is rejected by Davidson.

With these distinctions in mind, whilst there are undoubtedly things that we (or the race of congenital nine-year olds) are currently unable to understand — i.e. cases of epistemic ignorance — this does not mean that they cannot be conceptualised or expressed in a way that we do, or potentially could, understand. The notion of ‘conceivability’ can thus be seen to possess two separate but related components: (i) a cognitive or broadly epistemic component, i.e. understanding, and (ii) a semantic component, i.e. expressibility. If we read Nagel’s analogy as a claim about the congenital nine-year olds’ (or our own) ability to understand complex facts then it constitutes a relatively unobjectionable empirical claim concerning the first component: understanding. In order to carry this conclusion over to the second component, however, there must also be some fixed limit to the ability to acquire new knowledge and concepts such that the relevant epistemic and/or conceptual ignorance could never be overcome, thus creating a case of cognitive inadequacy. Unfortunately for Nagel, it is far from clear that any such limit exists, even in the case of the congenital nine-year olds. This is especially true if we take future evolutionary and technological developments into account, since even they may be able to extend their cognitive abilities through education and technology, for example. Furthermore, it seems that even complex facts such as Maxwell’s equations could be expressed in (i.e. translated into) the nine-year olds’ language, regardless of their current ability to understand them.6 Indeed, this is precisely the point of Davidson’s argument, which relates to the semantic component of conceivability. Thus, Nagel’s analogy fails to demonstrate that there may be inconceivable — in the sense of unconceptualisable — facts. Rather, it only warrants the much weaker conclusion that we can never be certain whether our ignorance of certain facts is due to a lack of knowledge (i.e. epistemic) or of practical ability (i.e. cognitive), since the two are indistinguishable from the perspective of the thinkers in question. Given that the one does not entail the other, the crucial question concerning the existence of unconceptualisable facts remains unanswered.

At this point we might be tempted to extend Nagel’s analogy to include truths that may be inconceivable to any finite being. However, once again we run into the same problem since it is impossible to say whether such truths are truly unconceptualisable, or whether it is merely the case that no thinking being has yet managed to grasp them. This does not mean that such facts could not, given sufficient time and effort, be understood, but in the absence of any further evidence, the argument merely results in a stand-off.

In order for his analogy to work, Nagel also requires that the notions of truth and falsity transcend our conceptual abilities, but it is difficult to see how the concepts of ‘truth’ and ‘fact’ can possibly apply to such cases. Discounting the possibility of epistemic ignorance, the purported facts must exist in a way that is totally inaccessible to all rational enquiry. This prompts the question of whether they can really be said to be part of reality at all, since anything that can affect us, whether directly or indirectly, can in principle be detected, and therefore subjected to analysis and conceptualisation. The same goes for any entity that supervenes upon known or knowable facts. A genuinely unconceptualisable fact must therefore possess a mode of existence that is not just divorced from the everyday life-world, but one that is independent of the very reality that we inhabit, since it cannot affect us in any way. Its ‘truth’ must be independent of any existent or possible language and yet still (in some presumably unfathomable way) be objectively determined by reality. At this point the notion of an ‘inconceivable fact’ begins to seem less like a philosophical thesis and more like mystical doctrine, since it is no longer clear in what sense such entities can be said to exist at all.

In summary, then, Nagel attempts to conclude from the finitude of our actual knowledge that there are limits upon possible knowledge, as expressed though language, rendering his argument invalid. His analogy appears to gain its plausibility from interpreting ‘inconceivability’ in terms of practical understanding, whereas Davidson’s argument addresses the semantic issue of conceptualisability. As such, the analogy does not represent a counterexample to Davidson. Indeed, even if we were to grant Davidson his conclusion that there are no inconceivable (i.e. unconceptualisable) facts, then this would not entitle us to conclude that whatever we cannot currently conceive of does not exist. Rather, in the absence of any fixed limit upon our cognitive abilities this remains an open question (thus addressing Nagel’s concerns for humility and anti-parochialism). What Nagel requires, but that his argument fails to provide, is some independent grounds for the existence of such a fixed limit upon cognition. In the absence of this, his case against Davidson is at best incomplete, and at worst unsuccessful, since the two accounts address different aspects of the notion of conceivability.

IV. Intertranslatability and Anti-Realism

In the final section of this essay I wish to consider the prospects for a compatibilist account of Davidson’s principle of intertranslatability and metaphysical realism of the kind that Nagel endorses. As we have seen, the Davidsonian may hold both that truths are translatable into any language (including that of the congenital nine-year olds) and that speakers of that language may, as a contingent matter of fact, be unable to understand them without rendering such facts ‘inconceivable’.7 Nagel alleges that this in itself represents a form of metaphysical idealism, since only entities that may be ‘idealised’ (i.e. conceptualised) are taken to form a part of reality (vfn 91). This is correct in so far as it attributes an anti-realist element to Davidson’s thought, but mischaracterises the nature of his position. As I argued in Section II, Davidson rejects the idealist claim that reality is constituted by our ideas and beliefs, although he does claim that belief has a role in determining the truth and falsity of our statements. What Davidson rejects is not realism as such, but the empiricist doctrine that mental entities — and specifically the mind itself — ‘mediate’ the connection between the world and knowledge (Evnine 1991: 149). In the absence of this doctrine, it can no longer be said that reality is wholly independent of our beliefs, but neither is it entirely dependent upon them since what it takes for a sentence to be true also involves our beliefs about the truth conditions of that sentence (Davidson 2001: 189–90). Whilst a detailed exposition of Davidson’s views lies outside the scope of this essay, it certainly seems possible that such an account of truth and reality can be given without falling into the kind of extreme subjectivism to which Nagel so strongly objects, and to which Davidson himself is opposed (ibid: 185).

Once we put Nagel’s central analogy to one side, his case for the link between conceivability and realism appears to rest on the contention that it is a necessary condition for the mind-independence of reality that it exceeds our capacity to conceive of it (vfn 91). However, it is far from clear why this should be the case since in order for reality to be ‘independent of the mental’, to use Devitt’s phrase, it is arguably sufficient that there are things that we do not know — i.e. cases of epistemic ignorance — regardless of what it is that we can know.8 This still allows the world to extend ‘beyond the reach of our minds’ (vfn 90), but not in the strong cognitive sense that Nagel’s argument demands. Furthermore, on the Davidsonian view, it is not that our being able to conceive of something is what ‘makes it real’ (vfn 92). Rather, it is the role that the world plays in constraining our beliefs, not independently of but in combination with language, that constitutes ‘reality’. This principle is never called into question by Davidson’s thesis of intertranslatability,9 although his rejection of empiricism does makes the relationship between thought and reality rather more difficult to define. Thus, the claims that everything is (at least potentially) conceivable and that the truth and falsity of our beliefs are not entirely dependent upon our epistemic powers do not, contrary to Nagel’s argument, appear to be entirely incompatible. The difference between the two positions lies not in the nature of reality per se, but rather in the relation between thought, reality and truth since for Nagel, thought and language are relatively independent of reality, whereas for Davidson the relationship is more complex.

V. Conclusion

Nagel’s argument for the link between the semantic and metaphysical questions with which I began this essay rests upon two main points, both of which turn out to be false. The first relates to his analogy of the congenital nine-year olds which, as I have argued, moves from an unobjectionable claim about the finitude of human knowledge to a more controversial and unsupported conclusion regarding the limits of conceivability. The second concerns the nature of conceivability itself, which I have argued has two different aspects. The source of the dispute between Nagel and Davidson regarding ‘inconceivable facts’ can be traced back to an equivocation between these two aspects — an error which also contributes to the apparent plausibility of Nagel’s central analogy. On Davidson’s interpretation of conceivability, however, the thesis of intertranslatability is not incompatible with the kind of realism that Nagel advocates — albeit with quite different implications for the relation between language, truth and reality. On this basis, Nagel’s argument fails to establish that conceivability and realism are in fact linked in the way that he supposes, making his objection to Davidson flawed, if not entirely misguided. This does not, however, mean that Nagel is wrong to think that reality must exceed our (potential) cognitive abilities any more than it means that Davidson’s view is correct. Rather, it merely shows that Nagel’s argument does not establish the falsity of Davidson’s thesis, and that the question concerning the link between metaphysics and semantics remains undecided.

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Bibliography

Devitt, Michael. 1984. Realism and Truth. Oxford: Basil Blackwell.

Davidson, Donald. 1984 (vics). ‘On the Very Idea of a Conceptual Scheme’. In Inquiries into Truth and Interpretation. Oxford: Clarendon Press, pp. 183–98.

—————  1990. ‘The Structure and Content of Truth’ (The Dewey Lectures 1989). Journal of Philosophy, 87, pp. 279–328.

—————  2001. Subjective, Intersubjective, Objective: Philosophical Essays, Volume 3. Oxford: Oxford University Press.

Dummett, Michael. 1978. Truth and Other Enigmas. London: Duckworth.

————— 2006. Thought and Reality. Oxford: Clarendon Press.

Evnine, Simon. 1991. Donald Davidson, Cambridge: Polity Press.

Feyerabend, Paul. 1962. ‘Explanation, Reduction, and Empiricism’. In Scientific Explanation, Space, and Time: Minnesota Studies in the Philosophy of Science, 3, pp. 82–.

Husserl, Edmund. 1969. Die Krisis der Europäischen Wissenschaften und die Transzendentale Phänomenologie. Hamburg: Verlag.

Kant, Immanuel. 1989. Critique of Pure Reason. P. Guyer and A. W. Wood (trans. and eds.). Cambridge: Cambridge University Press.

Kuhn, Thomas S. 1962. The Structure of Scientific Revolutions. Chicago: University of Chicago Press.

Nagel, Thomas. 1986 (vfn). ‘Thought and Reality’. In The View From Nowhere. Oxford: Oxford University Press, pp. 90–109.

Quine, W. V. O. 1951. ‘Two Dogmas of Empiricism’. The Philosophical Review, 60, pp. 20–43

Wright, Crispin. 1992. Truth and Objectivity. Cambridge, Massachusetts: Harvard University Press.

—————  1993. Realism, Meaning and Truth. Oxford: Blackwell.