(I.) The cup in front of me contains a deadly infusion of hemlock that will kill anyone who drinks it.
And:
(II.) I do not want to die by drinking it.
And:
(III.) There is no oughtness — moral or otherwise — or any other reason whatsoever that I ought to drink it.
Therefore,
(IV.) I ought not to drink it.
But, hold on:
(Va.) Oughtness is not a kind of isness (i.e., is not a fact); and (Vb.) Oughtness cannot be rationally derived from isness. (Add: the same goes for what purports to be oughtness.)
And:
(VI.) Conclusion IV is an oughtness — or rather, purports to be.
Therefore,
(VII.) Conclusion IV is neither an isness (i.e., neither a fact) nor rationally derived, after all, from the isnesses (i.e., the facts) of I, II and III.
And:
(VIII.) That which is neither a fact nor rationally derived from at least one fact is of dubious validity, to say the least, gaining credence only through error or fallacy.
Therefore,
(IX.) Conclusion IV is of dubious validity, to say the least, gaining credence only through error or fallacy.
And:
(X.) I do not give credence to what is neither a fact nor rationally derived from at least one fact; to what is gained through error or fallacy; hence to what is of dubious validity.
Therefore,
(XI.) I do not give credence to IV, namely, that I ought not to drink the deadly infusion.
[The irrational crux of the matter lies in the twin-beliefs that (Va.) oughtness is not a kind of isness and that (Vb.) oughtness cannot be rationally derived from isness: namely, it lies in eighteenth-century follies that still blight the intellectual landscape.
Now, those who wish to maintain their defence of Va and Vb and yet who also wish somehow (but understandably) to find that the argument from I-IV is reasonable (despite holding Va: oughtness is not a kind of isness) will likely suggest that the oughtness in conclusion IV, namely, that I ought not to drink the hemlock, is not derived from the isness of the premises at all but rather from an oughtness implicit in premise III, namely, that there is no oughtness — moral or otherwise — or any other reason whatsoever that I ought to drink the hemlock. Here there are a few things to note.
(1) Premise III is not an ought-statement but an is-statement that embeds an ought-statement in its denial of oughtness. In the case that it is true, it is true by the isness (i.e., the fact) either that there is in fact no oughtness in the world, or that just in this case there is none.
(2) Conclusion IV is derived from the whole of premise III, not just from an embedded part of it, as well as from premises I and II, and since each premise as a whole is an is-statement, and if conclusion IV is rationally derived from the premises, then it follows that oughtness can be rationally derived at least in part from isness. Or: the paradigm of premise III, namely, It is not the case that I ought to do, is not logically equivalent to the paradigm of conclusion IV, namely, I ought not to do, hence the latter does not by itself logically follow from the former, hence furthermore, if the conclusion is rationally drawn from the premises, then part of it must be rationally derived from the isness of the premises, contrary to the claim of Vb. (In short, the oughtness of conclusion IV cannot be derived solely and in particular from the denial of oughtness in premise III.)
(3) If it were then held by saving modification that Vb is after all just the claim that oughtness cannot be rationally derived solely from isness, where isness is assumed as utterly devoid of implicit oughtness, then the claim would be but a special case of nihil fit ex nihilo, a principle held to be true by reasonable men for millennia; but then it would lose its supposedly new and radical sting. In every rational argument, what is explicit in the conclusion is implicit in the premises, otherwise there would be nothing therein for logical inference to draw out into the conclusion. (And why should arguments with ought-conclusions be held to a higher — nay, impossible — standard?) So, indeed, the oughtness found in the conclusion of the argument I-IV is implicit in the premises. But that does not show Vb to be true as stated and meant (as a new and radical finding). For the claim of Vb as stated and meant is not that oughtness cannot be derived from oughtness, but that oughtness cannot be derived from isness, which presupposes for its truth that oughtness is not a kind of isness.
(4) What makes Vb new and radical (and false) is its presupposition of Va, namely, that oughtness is not a kind of isness. That is the real crux of the matter. And what shows the falsehood of Vb is the falsehood of Va, being that its contrary is true, namely, that oughtness is a kind of isness. (Naturally, just as there are false is-claims, so there are also false ought-claims.) That Va and Vb are false is clear in the light of intentionality.
But here it is pertinent to be reminded that some philosophers have also denied the existence of intentionality: of any kind of aboutness, end-directedness, or goal-tendency. (Their goal in doing so is not immediately clear.) Thus, for them, that oughtness cannot be rationally derived from isness follows from the “facts” (as they see them) that not only is oughtness not isness but also that nothing can be rationally derived, at least where that means logical inference towards an end. If they were so inclined, they ought to argue as follows:]
(I.) Nothing is about anything, or acts or is conducted towards, for, or to an end.
Untherefore,
(IIa.) No “logical inference” is about anything, or acts or is conducted towards, for, or to an end; and (IIb.) Nothing else in this “argument”, including its “premise” (I), nor the “argument” itself, is about anything, or acts or is conducted towards, for, or to an end: e.g., towards the end of understanding the world or an aspect of it. (As the quotation-marks, which in fact signify nothing, might suggest, if suggestion were possible, these are not things as ordinarily understood, to wit, as being about something, etc — but then of course neither is understanding, ordinary or otherwise.)
Untherefore,
(III.) Nothing follows, except perhaps and per accidens my lunch and the saying of new things, which will not be about anything, etc.
Still, whatever:
(IV.) Science is great, in spite of its not being about anything, etc — great not least in that it somehow helped to reveal its own insignificance in showing premise I, namely, that nothing is about anything, or acts or is conducted towards, for, or to an end.
[Here the eliminativist might argue that whilst science is not about anything, nor conducted by its practitioners towards, for, or to an end, it nevertheless reflects the world. He might do so, but he ought to bear in mind — though he might give the oughtness no credence — that his argument would, by his own lights, not be about science and its relation to the world, nor be conducted towards the end of defending its significance, although yet again he could say it reflects its significance, where “significance” does not bear any meaning of being about or towards something. But then, by those lights, he could say a lot of things about nothing to no end.]
