Truth3 対応説 |
対応説
what we believe or say is true if it corresponds to the way things actually are—to the facts
(対応説は)Aristotle、Aquinasにすでにあり
ムーア、ラッセルが対応説をとるに至った事情(同一説から対応説へ)
Moore (1899; 1902) and Russell (1904):the identity theory; a true proposition is identical to a fact 真な命題=事実(同一説)
Propositions are the primary bearers of truth
Moore and Russell came to reject the identity theory of truth in favor of a correspondence theory, sometime around 1910 (as we see in Moore, 1953, which reports lectures he gave in 1910–1911, and Russell, 1910b).
They do so because they came to reject the existence of propositions.
Why? Among reasons, they came to doubt that there could be any such things as false propositions, and then concluded that there are no such things as propositions at all. 偽な命題は偽な事実、偽な事実??ー命題そのものの放棄へ
「偽な命題」は(ムーアやラッセルにとって)なぜ問題だったのか
Why did Moore and Russell find false propositions problematic? A full answer to this question is a point of scholarship that would take us too far afield はるかに遠くへ.
(Moore himself lamented that he could not “put the objection in a clear and convincing way” (1953, p. 263), but see Cartwright (1987) and David (2001) for careful and clear exploration of the arguments.)
But very roughly, the identification of facts with true propositions left them unable to see what a false proposition could be other than something which is just like a fact, though false.
If such things existed, we would have fact-like things in the world, which Moore and Russell now see as enough to make false propositions count as true. Hence, they cannot exist, and so there are no false propositions.
As Russell (1956, p. 223) later says, propositions seem to be at best “curious shadowy things” in addition to facts.
From the rejection of propositions a correspondence theory emerges. The primary bearers of truth are no longer propositions, but beliefs themselves.
In a slogan:
A belief is true if and only if it corresponds to a fact.
Views like this are held by Moore (1953) and Russell (1910b; 1912).
対応説
The correspondence theory of truth is at its core an ontological thesis: a belief is true if there exists an appropriate entity—a fact—to which it corresponds. If there is no such entity, the belief is false.
ウィトゲンシュタインTractatus (1922)の影響
Facts, for the neo-classical correspondence theory, are entities in their own right. Facts are generally taken to be composed of particulars and properties and relations or universals, at least. The neo-classical correspondence theory thus only makes sense within the setting of a metaphysics that includes such facts. Hence, it is no accident that as Moore and Russell turn away from the identity theory of truth, the metaphysics of facts takes on a much more significant role in their views. This perhaps becomes most vivid in the later Russell (1956, p. 182), where the existence of facts is the “first truism.” (The influence of Wittgenstein's ideas to appear in the Tractatus (1922) on Russell in this period was strong, and indeed, the Tractatus remains one of the important sources for the neo-classical correspondence theory.
For more recent extensive discussions of facts, see Armstrong (1997) and Neale (2001).)