Toulmin’s Logical Types

Is the selection of a player for the Davis Cup of the same logical type as a prediction that a particular player will be selected, and as the normative judgment that a particular player deserves to be selected? It is not clear. Our prediction of a selection may turn out to be false without it being any less true that the player deserved to be selected. There may be a confusion here about a prediction being true (fulfilled) and it being the right prediction to make. The facts adduced are equally adequate to its being the right prediction to make and the player deserving selection (except that for the prediction we must assume additionally that the selector is aiming at selecting the most deserving player, and has access to the same information we do). In this sense of being the correct prediction, then, there does not seem to be a difference in logical type between this and the normative judgment. Also, whether this is the correct prediction is a fact about the prediction and is true or false when the prediction is made and depends on the evidence available when the prediction is made, and only indirectly about the event predicted, which may in fact never come about.

Thus, “deductively valid” is not another way of saying “analytic” or vice versa, and some arguments that are not deductively valid are nonetheless analytic, on this meaning of ‘analytic.’ This distinction is itself fraught with problems that I do not intend to discuss here. For a discussion see Hamby (2012). There is one comment that I would like to make though: I think that we are supposed to read the procedure of checking subjunctively, that is to say, an argument is analytic if, were you to check the backing, you would ipso facto check the conclusion. It does not, then, cease to be analytic because you may have already checked the backing [as Hamby (2012) seems to suggest], for it is still the case that checking the backing would involve checking the conclusion. When Toulmin (1958, p. 117) says that even such an argument “may slip… into the substantial class” he is not saying that, because checking the backing may be in the past, what he has just given as an analytic argument is not really analytic at all; rather, he is saying that when backing involves facts about the past, the conclusion must also be about the past if the argument is to be analytic, and if it is about the present it is substantial. Toulmin does not say that it is a problem that the checking is in the past, but that the facts checked are in the past. Just as we can check what is true now (e.g., by looking) we can check what was true in the past (e.g., by consulting written records). The checking itself is always subjunctively construed.

So, an argument whose backing involves facts about the past is still analytic if the conclusion is about the past, but is not when the conclusion is about the present, because what we have been (or would be) checking is a fact about the past and not the present. Since facts about the past and facts about the present are of different logical types such an argument must be substantial for Toulmin. Toulmin (1958, p. 117) says that the conclusion of this substantial argument is a presumption that something is true now. The time at which the checking is carried out is irrelevant, and, in fact, it need not actually be carried out—we can tell that an argument is analytic without actually checking the backing but by seeing that checking the backing involves checking the conclusion on the basis of their semantic content.

It is true, though, that there is no formal test for absurdity. It is presumed that this is something we can just “see,” or can be made to see once analysis has unmasked “disguised nonsense,” to use Wittgenstein's phrase.

See Botting (2014) for further discussion of how this issue has generally been mangled in argumentation theory.

Phenomenalism is not the only possible response: the others are transcendentalism and scepticism.

On Ayer’s account, our justification for using it, or for using a principle of induction at all, is that it has worked in the past (Ayer 1946, p. 18), while Reichenbach (1938) sets out to prove the conditional that induction will lead to the truth if anything will. Toulmin’s own comments on the justification of induction at pp. 217–221 are rather puzzling. I suspect that he makes the equivocation mentioned in footnote 1 between making a true prediction and making a correct prediction. A prediction may be the correct one to make when one has gathered all the evidence currently available and drawn inferences from it in the correct way. But what we really want to know is whether our predictions reliably turn out to be true. If induction did not lead to truth then it would not be justified in the sense at issue. The same goes for warrants, I might add.

Interestingly, Reichenbach (1938, pp. 64–67) does provide a way of making sense of, e.g., theological claims, by using his idea of a coordinative definition. A claim, for example, that cats are divine, is coordinated to some property of cats that inspires awe in its worshippers. The theological term “divine” has empirical criteria of application, and every action that follows upon the belief that a particular cat is divine follows also on the belief that the cat has the coordinated empirical property. This seems to mean that we can reason from cats being divine, but does not mean that we can argue to it, that is to say, establish it as a conclusion. In other words, it does not show that cats are actually divine, which is what interests us here.

In particular, by concatenating our inductions. See Reichenbach (1938), and especially his discussion of the cubical world in §14 and §15 for a probabilistic justification of belief in the external world. Statements about the external world can be given a weight, and this independently of any single inductive argument for the statement, though dependently of inductive arguments as a whole.

This can be seen in Reichenbach, where in the end it seems to be because it is not possible not to act—we must act and consequently must take our best wager as the basis of our action—that induction is vindicated. Since the action that follows on our best wager is the same as what would follow if we knew the proposition to be true, we can even co-ordinate truth with our best wager.