Friday, June 10, 2011

What is Truth?

For some reason, it appears to be my week for philosophy. That being so, the fundamental question occurs: what is truth? That question is quite relevant for the philosophical foundations of economic methodology and politics, but this post is basically one on philosophy. If philosophy isn’t your cup of tea, then skip this post. I take my account below from Scruton (1994: 97–111), which I have always found to be a useful book and good starting point for discussing philosophy.

There is a difference between (1) substantive theories of truth and (2) deflationary theories. The latter hold that truth is a concept that is dispensable or merely useful. These are the major theories of truth that have held by various philosophers and logicians:
Theories of Truth
I. Substantive Theories
(1) Correspondence Theory (a metaphysical theory of truth)
(2) Tarski’s Semantic Theory
(3) Coherence Theories (an epistemic theory of truth)
- (a) Postmodernist Coherence Theory
(4) Pragmatic Theories (Peirce, James and Dewey)
II. Deflationary Theories
(1) Redundancy Theory
(2) Prosentential Theory (a modern version of (1))
(3) Performative Theory
(4) Tarski’s Semantic theory (possibly a version of the correspondence theory
(5) Disquotationalism
(6) Horwich’s minimalism
The substantive theories of truth regard truth as a real and important property.

I support the correspondence theory of truth. Truth is a relational property of a well formed proposition and holds when that proposition corresponds with, describes, pictures or properly reflects the real world or reality in some sense. Well formed propositions are the content of grammatically correct and meaningful declarative sentences (= statements) when asserted by a speaker (and they can also be unspoken thoughts). The types of propositions are as follows:
Types of Propositions
(1) Propositions of fact;

(2) Propositions expressing aesthetic and moral judgements (propositions of value);

(3) Propositions of policy (declarative statements stating a course of action and usually contain the word “should”).
The correspondence theory of truth applies to (1), but there is intense debate about whether ethical propositions have objective truth. Although few people are really concerned by the thought that aesthetic propositions (e.g., “this painting is beautiful”) have a subjective truth only, the question of whether ethical propositions have objective truth has rather important and stark consequences for human political, social and economic decision making and life.

As noted above, according to the correspondence theory, truth is a property of well formed propositions of fact, and it consists in, or is made known by, the relation (or correspondence) between what that proposition asserts and some relevant portion of reality, which can be states of affairs, situations, events, objects, sequences of objects, and even abstract ideas and their relations such as sets, properties, types and so on. The easy way of saying this is simply that a proposition is true “when it corresponds to the facts.”

Complications arise when we move from concrete particulars and their relations to abstract concepts and universals and their relations, but, if one subscribes to a moderate realism, these abstract phenomena (such as mathematics and so on) can also be included as part of reality, in the sense that universals are instantiated in concrete particulars, although there is no separate realm where universals themselves exist (as in extreme Platonic realism).

In epistemology, realism entails that concrete particulars have a real existence that is independent of the act of human perception. The question of how abstract concepts and universals exist is still controversial.

The correspondence theory of truth was held by Plato, Aristotle, Carneades, Thomas Aquinas, Descartes, Locke, Leibniz, Hume, Kant, G. E. Moore, Bertrand Russell, and J. L. Austin.


In grammar, there are four types of sentences, as follows:
Types of Sentences
(1) Statements = Declarative sentences
(a) indicative statement = proposition
(b) negative (indicative) statement = proposition
(c) subjunctive

(2) Commands (imperatives), Wishes, Requests, Concessions
(a) commands
(b) prohibitions (negative commands)
(c) wishes
(d) concession

(3) Questions
(a) Yes/no questions
(b) not yes/no questions

(4) Exclamations
(a) exclamatory sentences
(b) elliptical exclamatory sentences
(c) interjections
It is sentences of type (1) (a) and (b) that are propositions in the sense of logic and that have truth as a property.

Questions, commands, and exclamations do not have truth-value. This they are neither true nor false. There seems to be some confusion about whether a sentence in the subjunctive mood can have a truth value. A statement in the subjunctive mood asserts what ought to be, might be, may be, is believed to be, or hoped to be. A counterfactual conditional (or type of subjunctive conditional/remote conditional) is a statement of the form:
“if it had been the case that p, then it would have been the case that q” (a past tense subjunctive, implying in the antecedent that this refers to hypothetical events in the past), or

“if it were the case that p, then it would be the case that q” (implying possible present or future hypothetical situation or even a timeless one),
where the “if …” sentence is the subordinate clause (and protasis/antecedent), and the “then …” sentence is the main clause (and apodosis/consequent). In the counterfactual conditional we seem to need a protasis/antecedent that is false (and some argue that the antecedent must be false in a genuine counterfactual conditional).

For example, do sentences like this have truth?:
(1) It might rain tomorrow.
(2) It may have rained on Wednesday, 7 June 856 A.D. in Rome, Italy.
(3) That might be the same person I saw yesterday in the park.
(4) If Caesar had not been killed, then he would have conquered Parthia.
The status of such sentences and whether they have truth value seems controversial.


Scruton, R. 1994. Modern Philosophy: An Introduction and Survey, Sinclair-Stevenson, London.

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