Aristotle said in his book, Rhetoric:

'Thus every action must be due to one or other of seven causes: chance, nature, compulsion, habit, reasoning, anger, or appetite.'

Within this, he notes that all actions are due either to emotion or reason and that we seek pleasant things and act to reduce pain, thus predating Freud's pleasure-pain principle by over 2000 years.
Chance

Chance events affect us all the time and, although some have little effect in changing what we do, a number of others force us to act or otherwise motivate us into action.

'The things that happen by chance are all those whose cause cannot be determined, that have no purpose, and that happen neither always nor usually nor in any fixed way.'