Human good turns out to be activity of soul exhibiting excellence, and if there is more than one sort of excellence, in accordance with the best and most complete.Foroneswallowdoesnot makea summer, nor does one day; and so too one day, or a short time, does not make a man blessed and happy.

-Aristotle
Nicomachean Ethics, bk.1, ch.7,1098 (translated by Sir David Ross).

All the untidyactivity continues, awful but cheerful.

-Bishop, Elizabeth
  'The Bight'.

Imagination should be integrated with life, not turned into a separate activity, art, that monopolizes one's whole existence.

-Dudek, Louis
Collected in Notebooks1960^1994 (1994).

Hislife was oneround of activity which hehimself might deplore but was powerless to prevent.

-Leacock, Stephen Butler
  Sunshine Sketches of a Little Town,'The Ministrations of the Rev. Mr. Drone'.

No physical activity is so vain as boxing. A man gets into the ring to attract admiration. In no sport, therefore, can you be more humiliated.

-Mailer, Norman Kingsley
  The Fight.

In communist society, where nobody has one exclusive sphere of activity but each canbecomeaccomplished in any branch he wishes, society regulates the general production and thus makes it possible for me to do one thing todayand another tomorrow, to hunt in the morning, fish in the afternoon, rear cattle in the evening or criticize after dinner, just as I desire, without ever becoming hunter, fisherman, shepherd or critic.

-Marx, Karl Heinrich
  The German Ideology (with Friedrich Engels).

Asthe strong man exults in his physical ability, delighting in such exercises as call his muscles into action, so glories the analyst in that moral activity which disentangles.

-Poe, EdgarAllan
  Of detective work.'The Murders in the Rue Morgue', in the Gentleman's Magazine, Apr.

In science men have discovered an activity of the very highest value in which they are no longer, as in art, dependent for progress upon the appearance of continually greater genius, for in science the successors stand upon the shoulders of their predecessors; where one man of supreme genius has invented a method, a thousand lesser men can apply it.

-Russell, Bertrand Arthur William Russell, 3rd Earl
  A Free Man'sWorship and Other Essays.