A theory of Justice: Revised Edition

particular kind of activity will be preferred. It says only that we prefer,
other things equal, activities that depend upon a larger repertoire of real-
ized capacities and that are more complex. More precisely, suppose that
we can order a certain number of activities in a chain by the inclusion
relation. This means that the nth activity exercises all the skills of the
n–1th activity and some further ones in addition. Now there are indefi-
nitely many such chains with no elements in common, let us say; and
moreover, numerous chains may start from the same activity representing
different ways in which this activity can be built upon and enriched. What
the Aristotelian Principle says is that whenever a person engages in an
activity belonging to some chain (and perhaps to several chains) he tends
to move up the chain. In general, he will prefer doing the nth to doing the
n–1th activity; and this tendency will be stronger the more his capacity is
yet to be realized and the less onerous he finds the strains of learning and
training. Presumably there is a preference for ascending the chain or
chains which offer the greatest prospects of exercising the higher abilities
with the least stress. The actual course that a person follows, the combi-
nation of activities that he finds most appealing, is decided by his inclina-
tions and talents and by his social circumstances, by what his associates
appreciate and are likely to encourage. Thus natural assets and social
opportunities obviously influence the chains that individuals eventually
prefer. By itself the principle simply asserts a propensity to ascend what-
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65. Aristotelian Principle

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ever chains are chosen. It does not entail that a rational plan includes any
particular aims, nor does it imply any special form of society.
Again, we may suppose, although it is probably not essential, that
every activity belongs to some chain. The reason for this is that human
ingenuity can and normally will discover for each activity a continuing
chain that elicits a growing inventory of skills and discriminations. We
stop moving up a chain, however, when going higher will use up re-
sources required for raising or for maintaining the level of a preferred
chain. And resources here is to be taken broadly, so that among the most
important ones are time and energy. This is the reason why, for example,
we are content to lace our shoes or to tie our tie in a straightforward way,
and do not ordinarily make complex rituals of these daily actions. There
are only so many hours in a day, and this prevents our ascending to the
upper limits of our capacity all the chains that are open to us. But then a
prisoner in a cell might take time with daily routines and invent ways of
doing them that he would not otherwise bother with. The formal criterion
is that a rational individual selects a preferred pattern of activities (com-
patible with the principle of justice) and proceeds along each of its chains
up to the point where no further improvement results from any feasible
change in the schedule. This overall standard does not, of course, tell us
how to decide; rather it emphasizes the limited resources of time and
energy, and explains why some activities are slighted in favor of others
even though, in the form in which we engage in them, they allow for
further elaboration.
Now it may be objected that there is no reason to suppose that the
Aristotelian Principle is true. Like the idealist notion of self-realization,
to which it bears a certain resemblance, it may have the ring of a philoso-
pher’s principle with little to support it. But it seems to be borne out by
many facts of everyday life, and by the behavior of children and some of
the higher animals. Moreover, it appears to be susceptible to an evolution-
ary explanation. Natural selection must have favored creatures of whom
this principle is true. Aristotle says that men desire to know. Presumably
we have acquired this desire by a natural development, and indeed, if the
principle is sound, a desire to engage in more complex and demanding
activities of any kind as long as they are within our reach.
21
Human
beings enjoy the greater variety of experience, they take pleasure in the
21. See B. G. Campbell,