Full Idea
Consciousness is the absolute reality, the measure of all existence; all that exists, exists only as being for consciousness, as comprehended in consciousness; for consciousness is first and foremost being.
Gist of Idea
Consciousness is absolute reality, and everything exists through consciousness
Source
Ludwig Feuerbach (Principles of Philosophy of the Future [1843], §17)
Book Reference
Feuerbach,Ludwig: 'Principles of the Philosophy of the Future', ed/tr. Vogel,M [Hackett 1986], p.27
A Reaction
This is Feuerbach declaring himself in favour of idealism even as he was trying to rebel against it, and move towards a more sensuous and human view of the world. I just see idealists as confusing ontology and epistemology.