Full Idea
It is because contemplation is an activity that is not also a process that Aristotle identifies it as the most final good.
Gist of Idea
Contemplation is final because it is an activity which is not a process
Source
Christine M. Korsgaard (Aristotle and Kant on the Source of Value [1986], 8 'Activity')
Book Reference
Korsgaard,Christine M.: 'Creating the Kingdom of Ends' [CUP 1996], p.239
A Reaction
Quite a helpful way of labelling what Aristotle has in mind. So should we not aspire to be involved in processes, except reluctantly? I take the mind itself to be a process, so that may be difficult!
Related Idea
Idea 18239 What is contemplated must have a higher value than contemplation [Kant, by Korsgaard]