Instinct is untaught ability.

Instinct is the nose of the mind.

Instinct is action taken in pursuance of a purpose, but without conscious perception of what the purpose is.

A goose flies by a chart which the Royal Geographical Society could not mend.

Intuition and concepts constitute... the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts, can yield knowledge.

The active part of man consists of powerful instincts, some of which are gentle and continuous; others violent and short; some baser, some nobler, and all necessary.