This follows up on yesterday's discussion. Thanks to Hodges for getting me started on this, to Milos for reminding me of MacIntyre, and to Peter for agreeing with me so far.
Are there any valid arguments that satisfy the following conditions: (i) The premises are all factual in the sense of purporting to state only what is the case; (ii) the conclusion is normative/evaluative? Alasdair MacIntyre gives the following example (After Virtue, U. of Notre Dame Press, 1981, p. 55):
1. This watch is inaccurate.
2. This is a bad watch.
MacIntyre claims that the premise is factual, the conclusion evaluative, and the argument valid. The validity is supposed to hinge on the functional character of the concept watch. A watch is an artifact created by an artificer for a specific purpose: to tell time accurately. It therefore has a proper function, one assigned by the artificer. (Serving as a paperweight being an example of an improper function.) A good watch does its job, serves its purpose, fulfills its proper function. MacIntyre tells us that "the concept of a watch cannot be defined independently of the concept of a good watch . . ." and that "the criterion of something's being a watch and something's being a good watch . . . are not independent of each other." (Ibid.) MacIntyre goes on to say that both sets of criteria are factual and that for this reason arguments like the one above validly move from a factual premise to an evaluative conclusion.
Speaking as someone who has been more influenced by the moderns than by the ancients, I don't see it. It is not the case that both sets of criteria are factual in the sense defined above. The criteria of something's being a good watch already contains evaluative criteria. For if a good watch is one that tells time accurately, then that criterion of chronometric goodness involves a standard of evaluation. If I say of a watch that it is inaccurate, I am not merely describing it, but also evaluating it. MacIntyre is playing the following game, to put it somewhat uncharitably.
He smuggles the evaluative attribute good into his definition of 'watch,' forgets that he has done so thereby generating the illusion that his definition is purely factual, and then pulls the evaluative rabbit out of the hat in his conclusion. It is an illusion since the rabbit was already there in the premise. In other words, both (1) and (2) are evaluative. So, while the argument is valid, it is not a valid argument from a purely factual premise to an evaluative conclusion.
So if the precise question is whether one can validly move from a purely factual or descriptive premise to an evaluative conclusion, then MacIntyre's example fails to show that this is possible.
But I am being tendentious on purpose for didactic reasons. I grant that it is not perfectly evident that values and facts are mutually exclusive. I think what MacIntyre needs is the idea that some statements are both factual and evaluative. If (1) is both, the MacIntyre gets what he wants.
Is Man a Functional Concept?
But suppose one would be wrong to reject the (1)-(2) counterexample and that, with respect to functional concepts, the move from fact to value is logically kosher. Then this discussion is relevant to ethics, the normative study of human action, only if man is a functional concept. Aristotle maintains as much: man qua man has a proper function, a proper role, a proper 'work' (ergon). This is a proper function he has essentially, by his very nature, regardless of whatever contingent roles a particular human may instantiate, wife, father, sea captain. Thus, " 'man' stands to 'good man' as 'watch' stands to 'good watch' . . . ." (56) Now if man qua man has a proper and essential function, then to say of a particular man that he is good or bad is to imply that he has a proper and essential function. But then to call a man good is also to make a factual statement. (57)
The idea is that being human is a role that includes certain norms, a role that each of us necessarily instantiates whether like it or not. There is a sort of coalescence of factual individual and norm in the case of each human being just as, in Aristotle's ontoloogy, there is a sort of coalescence of individual and nature in each primary substance.
But does man qua man have a proper role or function? The moderns fight shy of this notion. They tend to think of all roles, jobs, and functions as freely adopted and contingent. Modern man likes to think of himself as a free and autonomous individual who exists prior to and apart from all roles. This is what Sartre means when he says that existence precedes essence: Man qua man has no pre-assigned nature or essence or proper function: man as existing individual makes himself what ever he becomes. Man is not God's artifact, hence has no function other than one he freely adopts.
Although Aristotle did not believe in a creator God, it is an important question whether an Aristotle-style healing of the fact-value rift requires classical theism as underpinning. MacIntyre seems to think so. (Cf. p. 57)
If the precise question is whether one can validly move from a purely factual or descriptive premise to an evaluative conclusion, I have yet to see a clear example of this. But one ought to question the strict bifurcation of fact and value. The failure of entailment is perhaps no surprise given the bifurcation. The Aristotelian view, despite its murkiness, remains a contender.