MacIntyre on the Is-Ought Problem

In a previous post, I introduced the so-called "Is/Ought Problem," first made famous by David Hume.  Hume argued that you cannot get from an "is" to an "ought"-- that is, you cannot argue from the way that things currently are, to the way that things ought to be.  Or more generally, you cannot get from factual statements to evaluative statements.  But this is exactly how many people argue in a moral context-- "punching someone causes them pain, therefore you should not punch someone," for example. Or "James is fast and strong. He should play football." But is this true?  Is it always uncalled for to argue from premises involving the way things are, to conclusions involving the way things ought to be?

In After Virtue, Alasdair MacIntyre gives several counter-examples for why this is not the case.  Consider first:

There are several types of valid argument in which some element may appear in a conclusion which is not present in the premises. A.N. Prior's counter-example to this alleged principle illustrates its breakdown adequately; from the premise 'He is a sea-captain', the conclusion may be validly inferred that 'He ought to do whatever a sea-captain ought to do'. This counter-example not only shows that there is no general principle of the type alleged; but it itself shows what is at least a grammatical truth - an 'is' premise can on occasion entail an 'ought' conclusion. [1]

You can see here that the reason this example succeeds is because there is a concept of "Sea Captain" which entails certain responsibilities.  Those responsibilities are built into what it means to be a sea captain.  Thus the counter-example adequately shows why Hume's contention is wrong, at least in some cases.  Consider further:

From such factual premises as 'This watch is grossly inaccurate and irregular in time-keeping' and 'This watch is too heavy to carry about comfortably', the evaluative conclusion validly follows that 'This is a bad watch'. From such factual premises as 'He gets a better yield for this crop per acre than any farmer in the district', 'He has the most effective programme of soil renewal yet known' and 'His dairy herd wins all the first prizes at the agricultural shows', the evaluative conclusion validly follows that 'He is a good farmer'.  

Both of these arguments are valid because of the special character of the concepts of a watch and of a farmer. Such concepts are functional concepts; that is to say, we define both 'watch' and 'farmer' in terms of the purpose or function which a watch or a farmer are characteristically expected to serve. It follows that the concept of a watch cannot be defined independently of the concept of a good watch nor the concept of a farmer independently of that of a good farmer; and that the criterion of something's being a watch and the criterion of something's being a good watch-- and so also for 'farmer' and for all other functional concepts-- are not independent of each other. [...]  

Now clearly both sets of criteria-- as is evidenced by the examples given in the last paragraph-- are factual. Hence any argument which moves from premises which assert that the appropriate criteria are satisfied to a conclusion which asserts that 'That is a good such-and-such', where 'such-and-such' picks out an item specified by a functional concept, will be a valid argument which moves from factual premises to an evaluative conclusion. Thus we may safely assert that, if some amended version of the 'No "ought" conclusion from "is" premises' principle is to hold good, it must exclude arguments involving functional concepts from its scope. But this suggests strongly that those who have insisted that all moral arguments fall within the scope of such a principle may have been doing so, because they took it for granted that no moral arguments involve functional concepts. [2]

So we have two examples of arguments which start from premises stating only the way things are, to a conclusion that entails some evaluative judgement.  MacIntyre rightly points out that at this point Hume's defenders can only proceed by modifying their principle.  Perhaps it is the case that evaluative conclusion can (in some cases) proceed from factual premises.  Perhaps instead, the principle is only true from those arguments which do not involve functional concepts.  But this shift identifies and magnifies the breakdown of the Enlightenment attempt to justify morality rationally, a major thesis of MacIntyre's book:

Yet moral arguments within the classical, Aristotelian tradition-- whether in its Greek or its medieval versions-- involve at least one central functional concept, the concept of man understood as having an essential nature and an essential purpose or function; and it is when and only when the classical tradition in its integrity has been substantially rejected that moral arguments change their character so that they fall within the scope of some version of the 'No "ought" conclusion from "is" premises' principle. That is to say, 'man' stands to 'good man' as 'watch' stands to 'good watch' or 'farmer' to 'good farmer' within the classical tradition. Aristotle takes it as a starting-point for ethical enquiry that the relationship of 'man' to 'living well' is analogous to that of 'harpist' to 'playing the harp well' (Nicomachean Ethics, 1095a 16). But the use of 'man' as a functional concept is far older than Aristotle and it does not initially derive from Aristotle's metaphysical biology. It is rooted in the forms of social life to which the theorists of the classical tradition give expression. For according to that tradition to be a man is to fill a set of roles each of which has its own point and purpose: member of a family , citizen, soldier, philosopher, servant of God. It is only when man is thought of as an individual prior to and apart from all roles that 'man' ceases to be a functional concept. [3]

Thus the failure involves not a simple disagreement with classical thinkers (the predecessor culture, as MacIntyre calls it), but a wholesale rejection of the classical worldview, whereby "man" was understood to have an essential nature.  And this essential nature involves functional concepts.  To say a man is a "good man" is no different from saying a watch is a "good watch," a farmer is a "good farmer," or a sea-captain is a "good sea-captain" on the classical view.  Each of these is true in virtue of the role that they play, and the functionality which they essentially exhibit. 

So given Hume's presuppositions (a complete rejection of the classical worldview, especially the idea of man's essential nature and telos), he may have been right that morally evaluative conclusions could not be derived from factual premises.  However, these presuppositions (shared by many Enlightenment and post-Enlightenment thinkers) are not obviously true.

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Notes:

1. MacIntyre, 1981, p.57

2. Ibid. pp.57-58

3. Ibid. pp.58-59