it. Referring back to our discussion about the importance of falsification we can see how much more conclusive evidence has to be in order to provide reasons for falsification. Thinking, then, of what a moral fact would be in order to determine, by Dummett's standards, whether moral
language is warranted: Are moral claims ever asserted on the basis of inductive evidence? And, in the light of much uncertainty about what exactly a moral fact looks like, are ever going to be able to deny moral claims?
therefore that from the premise of truth being directly related to the notion of truth conditions we must deduce that the middle, that possibility of some statements not either meeting or not meeting their truth conditions, is excluded. In effect, what has just been described is the Law of Bivalence;
which states that "there are exactly two truth values, true and false, and that, within a certain area of discourse, every statement has exactly one of them" (Penguin Dictionary of Philosophy; 78).
But it seems that, when truth is regarded an epistemic notion, and we cannot rest content with a conditional way (meeting hypothetical truth conditions) of defining truth, we must allow for the determinate truth value of some statements not being obtainable. The reason for this is simple: if the speaker does not have the necessary knowledge to establish whether or not a statement does or can meet its truth conditions then this statement remains indeterminate (because determinacy is something which depends on some cognitive relationship between the speaker and the conditions which would make the statement true). This means that according to an evidentially constrained notion of truth indeterminacy is a real possibility.
The linguistic turn in philosophy saw, among other things, an adoption by some of an epistemic notion of truth. The reason for this is that analytical philosophy, as we have said in chapter one, is premised on empirical (scientific) foundations, which occurred as an attempt to counter the obscure and highly speculative philosophy which had, up until that point, been the order of the day. We know science, in part, for one defining quality it has; that all legitimate and respectable scientific theories must, at least, be testable (by the proponents of and oppositions to the theory). It is exactly this principle, the testability of scientific theories, which gives rise to an evidentially constrained notion of truth. This is because a truth conditional understanding of truth does not, in itself, require the speaker (scientist) to demonstrate or explain how the truth of his/her claim (theory), can be
verified (tested). I suggest, regarding the matter of truth, that if we claim to be saying something true, and we are averse to the slippery slope of a speculative philosophy, we must by necessity commit to an evidentially constrained notion of truth.
What we have so far then is a commitment to truth as evidentially constrained. Adopting this conception of truth must have certain implications for some foundational principles of philosophy.
The rest of this chapter consists of an investigation of whether or not it is possible to continue endorsing Classical Logic when one of the foundational principles, the Principle of Bivalence, cannot be sustained under an epistemic notion of truth. The conclusion is that it may stand to reason to reject Classical Logic in situations where no evidence is available for the determining of the truth or falsity of a proposition.
Classical logic is based on the rule of the excluded middle, and truth as evidence transcendent is regarded, therefore, by some (such as Dummett) as the cornerstone of Classical Logic.
Classification of the conclusions of arguments as determinately true or false, and even just basic assertions as always being either true or false, or assuming that they will be either true or false under ideal epistemic conditions, means that we have excluded the possibility that some assertions and some conclusions of arguments may not be either of these values for the reason that not all epistemic conditions are ideal. Classical logic regards the fact that we sometimes just do not have access to the facts or non-existence of facts as irrelevant to the definition of truth.
The problem with the type of reasoning that maintains all assertions are either true or false is that it is guilty of begging the question. (Begging the question being when an argument assumes at the level of its premises what it is central to its conclusion.) By excluding the logical possibility of some propositions being neither true nor false, the Principle of Bivalence assumes that the nature of
knowledge is such that propositions about the world can be treated in the same way as
mathematical and logical propositions. When it is maintained that our propositions will always be either true or false, whether we are capable of showing this or not, we must be appealing to an evidence transcendent notion of truth. Evidence transcendent truth may be appropriate for situations wherein the truths of propositions will be, when settled, necessary truths. The reason is most likely related to the fact that rational proofs are not based on contingent knowledge. And it is for the reason that the real world is not one of necessity that evidence of contingent facts must settle truths about reality. And tautologies, such as the Principle of Bivalence, even though useful in mathematics and formal logic, are unhelpful when it comes to knowledge about contingent
existence and therefore Classical logic begs the very question at heart (what is true about reality) when it assumes that such truths can be settled in the same way as analytical truths.
We have concluded that not all propositions are determinate in truth value. Additionally it is
proposed that moral propositions are of the "indeterminate in truth value" kind because they are not analytically true and so must be synthetically so. But if truth is evidentially constrained, is the claim, it is hard to see what sort of contingent knowledge will settle the truth of moral propositions.
My contention is therefore that no respectable category of knowledge, the synthetic a posteriori and the analytic a priori, has successfully accounted for moral properties and therefore moral facts.
It now remains to be seen what such a conclusion entails for the meaning of moral propositions.
CHAPTER 5
Truth and meaning; If truth is evidentially constrained then what is meaning?