These are truly beautiful words from Robert G Ingersoll, as taken from the superb site which has a fine selection of his writing, curated by a friend of mine:
Reason and the Brain
Nature has furnished every human being with a light more or less brilliant, more or less powerful. That light is Reason; and he who blows that light out, is in utter darkness. It has been the business of the church for centuries to extinguish the lamp of the mind.
Reason is the light, the sun, of the brain. It is the compass of the mind, the ever-constant Northern Star, the mountain peak that lifts itself above all clouds.
To me reason is the final arbiter, and when I say reason, I mean my reason. It may be a very poor light, the flame small and flickering, but, after all, it is the only light I have, and never with my consent shall any preacher blow it out.
I admit that reason is a small and feeble flame, a flickering torch by stumblers carried in the starless night, – blown and flared by passion’s storm, – and yet it is the only light. Extinguish that, and naught remains.
The dark continent of motive and desire has never been explored. In the brain, that wondrous world with one inhabitant, there are recesses dim and dark, treacherous sands and dangerous shores, where seeming sirens tempt and fade; streams that rise in unknown lands from hidden springs, strange seas with ebb and flow of tides, resistless billows urged by storms of flame, profound and awful depths hidden by mist of dreams, obscure and phantom realms where vague and fearful things are half revealed, jungles where passion’s tigers crouch, and skies of cloud and blue where fancies fly with painted wings that dazzle and mislead; and the poor sovereign of this pictured world is led by old desires and ancient hates, and stained by crimes of many vanished years, and pushed by hands that long ago were dust, until he feels like some bewildered slave that Mockery has throned and crowned.
The intellect is not always supreme. It is surrounded by clouds. It sometimes sits in darkness. It is often misled – sometimes, in superstitious fear, it abdicates. It is not always a white light.
The passions and prejudices are prismatic – they color thoughts. Desires betray the judgment and cunningly mislead the will.
The complex, tangled web of thought and dream, of perception and memory, of imagination and judgment, of wish and will and want – the woven wonder of a life – has never yet been raveled back to simple threads.