Full Idea
Consciousness exists to the extent that consciousness is useful.
Gist of Idea
Consciousness exists to the extent that consciousness is useful
Source
Friedrich Nietzsche (Writings from Late Notebooks [1887], 02[95])
Book Reference
Nietzsche,Friedrich: 'Writings from the Late Notebooks', ed/tr. Bittner,Rüdiger [CUP 2003], p.78
A Reaction
This strikes me as being a great truth, first because it emphasises the necessity of giving an evolutionary (survival) explanation of consciousness, and also because it invites us to consider the 'extent' to which we are conscious of brain activity.