Are there any (non-trivial) valid arguments that satisfy the following conditions: (i) The premises are all purely factual in the sense of purporting to state only what is the case; (ii) the conclusion is normative/evaluative? Alasdair MacIntyre gives an example (After Virtue, U. of Notre Dame Press, 1981, p. 55) that is plausible but not rationally coercive.
Substack latest.
I would say that it is part of the concept of a watch that its function is to measure time; indeed it’s hard to see how you could define that concept without referring to its function. But that it does so accurately is not part of the concept; rather, it’s implied by the concept, plus the (evaluative) premise “things ought to fulfill their proper functions, and they ought to do so as perfectly as their being material and limited permits”. A perfect watch would measure time with perfect accuracy; all real watches fall short of perfection, but that doesn’t put them outside the class of watches.
Now, the proper function of a watch is a fact (no one denies this, that I know of.) That it is good for a watch to be accurate follows so immediately from the general rule that it is good for anything to fulfill its proper function perfectly that it, too, can be taken for pure fact (for anyone not inclined to pedantry.) And nobody, not even the early modern skeptics who rejected Aristotle’s metaphysics, really denies the general rule either. The skeptics chose instead to deny that natural kinds have proper functions as part of their natures, apart from the intentions imposed on them by a rational designer.
Although I think the original intent behind the rejection of Aristotle wasn’t atheistic, but fideistic. Some Protestant theologians put so much emphasis on God’s omnipotence that they came to see norms built into nature as a limit on God, which was intolerable. So they followed the occasionalists and declared that God imposes norms on His creation as an artificer imposes functions on his artifacts.
At any rate, all we have to do to save the Aristotelian account of good and evil is the concede that the general rule “it is good for anything to fulfill its proper function perfectly” is technically evaluative, while pointing out that nobody actually denies that rule – the skeptics only deny its application.
>>But that it does so accurately is not part of the concept; rather, it’s implied by the concept, plus the (evaluative) premise “things ought to fulfill their proper functions, and they ought to do so as perfectly as their being material and limited permits”.<<
Quite right, which is why an evaluative conclusion does not follow directly from a purely factual premise.