The place of contemplation in Aristotle's Nicomachean Ethics ('NE') is genuinely puzzling. For a problem readily presents itself to which the solution is not obvious. I don't think Aristotle does reconcile his claims about virtuous activity and his claims about contemplation in his exposition. This does not mean that his ideas and arguments in text do not contain the material we need in order to effect the reconciliation on his behalf. Philosopher of immense greatness though he was, Aristotle did not leave his writings in a fully edited and finally revised state.
In a nutshell the answer is that we are complex natures - minds-and-bodies, matter and form. From this viewpoint the human good consists in virtuous activity; and in NE II.6 - V.15 Aristotle enumerates and specifies the various virtues, both moral and intellectual, appropriate to our complex natures. The catch is that one of the intellectual virtues, sophia or theoretical wisdom, yields a special and super-eminent good, namely contemplation, which is the most God-like and the closest we can attain to the pure life of intellect that the Gods (who are pure form) alone enjoy (NE X.8.1178b7-9). So we have to live embodied lives, the excellence of which consists in virtuous activity, while also giving expression to the best part of our nature, the virtue of theoretical wisdom exercised in contemplation, as occasion and opportunity allow.
The human good and contemplation
Consider the following line of thought, set out by David Charles.
1.In Nicomachean Ethics (N.E) I, Aristotle states that the
human good (or human well-being) is an activity of the soul in
accordance with virtue. He further claims that, if there are many
virtues, the human good is the activity of the soul in accordance
with the best and most goal-like of them (1098a16-18). He says
in N.E.X that the best of our virtues is that exercised when we
contemplate (1177a12ff). Therefore, he must take the human
good (or human well-being) to be intellectual contemplation.
2.Aristotle takes the human good to be the good (or goods) to
be achieved by humans (1097a22ff). Thus, if intellectual contem-
plation is the human good, it must be the best activity for
humans to pursue.
3.Therefore, he is right to conclude in N.E.X that intellectual
contemplation is the activity which humans ought always ration-
ally to pursue above all others (whenever and wherever possible:
While these claims are familiar, each needs to be made precise. The first and second are generally taken as identity statements:
 The human good = intellectual contemplation.
 The human good = the good to be achieved by humans.
From  and  it follows that, since ethically virtuous activity
is not a part of intellectual contemplation,
[3A] Ethically virtuous activity is not part of the human
good, and so is not part of the good to be achieved by
At best, such activity can have instrumental value in enabling
one to pursue intellectual contemplation. Thus, some suggest
that one cannot be a good contemplator without being generous,
courageous or practically wise, others that being virtuous makes
one better at contemplation.
 and  lead naturally to a further claim:
[3B] Principle of Choice: If a human is faced with a choice
between intellectual contemplation and some other
option, and is capable of both, she should always pursue intellectual contemplation (provided that the other
option does not tend to produce greater or better quality contemplation in the future).
(D. Charles, 'Aristotle on Well-Being and Intellectual Contemplation', Proceedings of the Aristotelian Society, Supplementary Volumes, Vol. 73 (1999), pp.
Virtuous activity versus contemplation
However, [3A] seems inconsistent with other elements of Aristotle's thinking in the Ethics. For elsewhere, virtuous activity
(including self-sacrificial courage) appears to have value independently of any connection with intellectual contemplation (in
one's own case or another's). Further, he nowhere suggests that
virtuous action is only to be pursued if it does not conflict with
intellectual contemplation, or if its pursuit leads to further (or
better) contemplation. Indeed, it is not clear that he thought that
virtue was required for excellence in contemplation, or that its
possession makes one better at contemplating. (D. Charles: 206.)
So why is intellectual contemplation the central or paradigm case of human well-being?
What is the significance of this claim for rational choice?
The answers to these questions are not spelled out in N.E.I.
Later, we learn that intellectual contemplation is the activity of
the best aspect of our nature, nous or theoretical intellect
(NE X.1177a 14-18). This claim, which reflects a metaphysical ordering
of our capacities, gives Aristotle some (contestable) ground for
taking contemplation as the central case of human well-being.
But, whatever its basis, it has important implications for the the-
ory of rational choice.
If intellectual contemplation is the paradigm case of the human
good, the activity of other virtues can also be instances of the
human good. Since the exercise of the virtue of our best aspect
is not identical with human well-being (as a whole), Aristotle can
avoid the principle of choice encapsulated in [3B] as follows.
 Theoria is the best activity of which we are capable
because it is the best activity of our best aspect (or
 However, we are not identical with our intellects alone.
 So, it does not follow that the best choice for us (as a
whole) is what is best for our best aspect (or part).
Indeed, since we have needs, capacities and desires other than
those which flow from the theoretical intellect, we should some-
times do what is best for us as a whole, and not what is best only
for our best aspect. It may, of course, be (from some perspective)
regrettable that our natures contain features other than the best
part. Perhaps those whose natures consist only in intellect will
lead better lives than we do. However, since our natures are com-
plex in this way, it will not follow from the fact that A is best
for the best part of us that A is best for us (as a whole). For, as
is sometimes remarked, something can be best for the best mem-
ber of a department (eg: giving her masses of research time), but not be best for the department as a whole. There is no inference
to [3B] from  and . (D.Charles: 218-9.)
D. Charles, 'Aristotle on Well-Being and Intellectual Contemplation', Proceedings of the Aristotelian Society, Supplementary Volumes, Vol. 73 (1999), pp.
Dominic Scott, 'Aristotle on Well-Being and Intellectual Contemplation', Proceedings of the Aristotelian Society, Supplementary Volumes, Vol. 73 (1999), pp.
W. F. R.Hardie, 1980, Aristotle's Ethical Theory, 2nd. ed. ch. XVI.