The Structure of the Realism Debate
Realism is common-sense: there really are facts about the world, these exist independently of our awareness of them and we can acquire knowledge in these domains.
Anti-realism is a critique of this naïve opinion deriving from conflict between the autonomy of facts and their accessibility necessitating some philosophical move to make these facts knowable. Anti-realist proposals about meaning, knowledge, truth and logic are alternative expressions of this basic dilemma.
Thus the conflict on a metaphilosophical level is between the Wittgensteinian view that philosophy leaves everything as it is and the more traditional view that philosophy can criticise and improve on existing conceptions.
In the philosophy of science, for example, this boils down to an anti-realist’s aversion to the realist’s naïve picture of facts that are both accessible and autonomous. Reactions to this dilemma range from denying that theoretical facts are autonomous i.e. that the theoretical facts are a subset of observational ones. Another reaction abandons accessibility, claiming that theoretical claims are not reducible to observation terms and consequently that they are not demonstrable on the basis of observable knowledge, resulting in scepticism and denial that truth is the proper aim of science. Another reaction still agrees that reductionism is false but that the sceptical response to this situation does not go far enough: the problem is not the knowledge of a theory but its intelligibility i.e. its truth or falsity, resulting in the same conclusion as the positivists that there is no distinct realm of theoretical facts. A fourth reaction would allow that there may be facts that go beyond what can be reduced to observational facts, but would deny that there can be facts that the canons of scientific verification would not enable us to discover.
In sum, the scientific realist believes in various distinctions that the anti-realist denies, in particular 1) the immediately observable facts, 2) the facts that are reducible by definition to observables, 3) the unobservable yet nonetheless verifiable theoretical facts, 4) the residue consisting of undiscoverable theoretical facts.
According to the anti-realist, these distinctions involve attributing to the theoretical facts an impossible combination of autonomy and accessibility. The sceptics resolve the tension by collapsing the distinction between the verifiable and the reducible; the reductionists and instrumentalists collapse, in different ways, the distinction between the totality of facts and the reducible facts; and the constructivists deny the distinction between the totality of facts and what is verifiable.
The Problem of Truth
What definition of truth are we using here? The two most popular competing answers are the correspondence theory and the verification theory. These are traditional inflated theories, yet there is no justification for preferring these above a deflationary account, in which we accept instances of the schema: ‘The proposition that p is true if and only if p’. The benefits of this account are: 1) it explains why we are so convinced that the proposition that snow is white is true if and only if snow is white; 2) it says why we have a concept of truth i.e. not to describe propositions but to enable a certain type of generalisation to be constructed (equivalence schema). Traditional theories identify truth with one or another analysible, complex property (such as correspondence with reality, coherence, pragmatic utility or provability), thus if the equivalence schema is right we can argue that such theories are mistaken. The schema is both necessary and sufficient for the truth predicate to perform its function, whilst providing an adequate definition of truth, a definition that needs no further characterisation in terms of an underlying nature.
Realism and Truth
Given the above, is it necessary for a realist or anti-realist to be persuaded of the deflationist account of truth and conversely for the deflationist to be either a realist or anti-realist? Horwich thinks no on both counts and concludes that the points at issue between the realist and anti-realists do not concern truth.
Moreover, other theories of truth as outlined above have no bearing on the debate. This might seem counterintuitive in the case of verificationism, since this theory would seem to bear on realism by promoting the accessibility of facts at the expense of their autonomy. But, Horwich argues, the arguments that might link the two are in fact instances of the equivalence schema. This is similar for the correspondence theory of truth. And yet, adopting the equivalence schema is no easier to establish than the realist or anti-realist theses it is being used to support. Thus, deflationism is neutral regarding realism.
We find ourselves in this position of confusing truth with realism because realists and anti-realists frequently employ the notion of truth, for example: ‘all truths are verifiable’, ‘theoretical hypotheses are truth-value-less’, ‘science aims at truth’, ‘no contingent statement about the future can be true’. These statements imply that they are about the property of truth and that one’s acceptance or rejection of them will be a reflection of what one thinks about that property. But, Horwich tells us that this reasoning is fallacious; the notion of truth appears in these theses as a device of generalisation (application of the equivalence schema). Even when the notion of truth is not deployed as a generalisation device, Horwich claims that the thesis in question could equally well have been articulated without the notion of truth; moreover, its reformulation in terms of truth is quite consistent with the deflationary position. For example, the instrumentalist thesis that theoretical knowledge is neither true nor false contains two implicit claims: 1) that theoretical sentences don’t express propositions and 2) that propositions are the bearers of truth and falsity. But the heart of the instrumentalists thesis clearly resides in the first claim and so has nothing to do with truth but moreover the assumption about truth in the second claim involves nothing that goes beyond deflationism.