Coherence theory of truth
Coherence theory of truth regards truth as coherence within some specified set of sentences, propositions or beliefs. There is no single set of such "logical universes", but rather an assortment of perspectives that are commonly discussed under this title. The model is contrasted with the correspondence theory of truth.
A positive tenet is the idea that truth is a property of whole systems of propositions and can be ascribed to individual propositions only derivatively according to their coherence with the whole. While modern coherence theorists hold that there are many possible systems to which the determination of truth may be based upon coherence, others, particularly those with strong religious beliefs hold that the such truth only applies to a single absolute system. In general, then, truth requires a proper fit of elements within the whole system. Very often, though, coherence is taken to imply something more than simple formal coherence. For example, the coherence of the underlying set of concepts is considered to be a critical factor in judging its coherence and validity. In other words, the set of base concepts in a universe of discourse must form an intelligible paradigm before many theorists consider that the coherence theory of truth is applicable.
Varieties of coherence theories
According to one view, the coherence theory of truth is the "theory of knowledge which maintains that truth is a property primarily applicable to any extensive body of consistent propositions, and derivatively applicable to any one proposition in such a system by virtue of its part in the system" (Benjamin 1962). Ideas like this are a part of the philosophical perspective known as theoretical holism (Quine & Ullian 1978). However, coherence theories of truth do not claim merely that coherence and consistency are important features of a theoretical system — they claim that these properties are sufficient to its truth. To state it in the reverse, that "truth" exists only within a system, and doesn't exist outside of a system.
According to another version of coherence theory, championed especially by H.H. Joachim, truth is a systematic coherence that involves more than logical consistency. In this view, a proposition is true to the extent that it is a necessary constituent of a systematically coherent whole. Others of this school of thought, for example, Brand Blanshard, hold that this whole must be so interdependent that every element in it necessitates, and even entails, every other element. Exponents of this view infer that the most complete truth is a property solely of a unique coherent system, called the absolute, and that humanly knowable propositions and systems have a degree of truth that is proportionate to how fully they approximate this ideal (Baylis 1962).
Coherence theories in specialized domains
Some versions of coherence theory have been claimed to characterize the essential and intrinsic properties of formal systems in logic and mathematics. A claim like this needs to be qualified by the observation that formal reasoners are content to contemplate axiomatically independent but mutually contradictory systems side by side, for example, the various alternative geometries. On the whole, coherence theories have been criticized as lacking justification in their application to other areas of truth, especially with respect to assertions about the natural world, empirical data in general, assertions about practical matters of psychology and society, especially when used without support from the other major theories of truth. The response has been that empirical data does not often form a consistent whole, and that truth should not be used in contexts where consistency fails.
Connections to other philosophical groups
Coherence theories distinguish the thought of continental rationalist philosophers, especially Spinoza, Leibniz, and G.W.F. Hegel, along with the British philosopher F.H. Bradley. They have found a resurgence also among several proponents of logical positivism, notably Otto Neurath and Carl Hempel.
Perhaps the best-known objection to a coherence theory of truth is Bertrand Russell's. Russell maintained that since both a belief and its negation will, individually, cohere with at least one set of beliefs, this means that contradictory beliefs can be shown to be true according to coherence theory, and therefore that the theory cannot work. However, what most coherence theorists are concerned with is not all possible beliefs, but the set of beliefs that people actually hold. The main problem for a coherence theory of truth, then, is how to specify just this particular set, given that the truth of which beliefs are actually held can only be determined by means of coherence.
- White, Alan R. 1969. 'Coherence Theory of Truth', Encyclopedia of Philosophy, Vol.2. Macmillan: 130-131.
- White, Alan R. 1969. 'Coherence Theory of Truth', Encyclopedia of Philosophy, Vol.2. Macmillan:131-133, see esp., section on "Epistemological assumptions"
- White, Alan R. 1969. 'Coherence Theory of Truth', Encyclopedia of Philosophy, Vol.2. Macmillan:130
- Baylis, Charles A. (1962), "Truth", pp. 321–322 in Dagobert D. Runes (ed.), Dictionary of Philosophy, Littlefield, Adams, and Company, Totowa, NJ.
- Benjamin, A. Cornelius (1962), "Coherence Theory of Truth", p. 58 in Dagobert D. Runes (ed.), Dictionary of Philosophy, Littlefield, Adams, and Company, Totowa, NJ.
- Kirkham, Richard L. (1992), Theories of Truth, MIT Press, Cambridge, MA.
- Quine, W.V., and Ullian, J.S. (1978), The Web of Belief, Random House, New York, NY, 1970. 2nd edition, Random House, New York, NY, 1978.
- Runes, Dagobert D. (ed., 1962), Dictionary of Philosophy, Littlefield, Adams, and Company, Totowa, NJ.