Nothing is too wonderful to be true, if it be consistent with the laws of nature.

I could trust a fact and always cross-question an assertion.

What a weak, credulous, incredulous, unbelieving, superstitious, bold, frightened, what a ridiculous world ours is, as far as concerns the mind of man. How full of inconsistencies, contradictions and absurdities it is. I declare that taking the average of many minds that have recently come before me ... I should prefer the obedience, affections and instinct of a dog before it.

Nature is our kindest friend and best critic in experimental science if we only allow her intimations to fall unbiased on our minds.

A man who is certain he is right is almost sure to be wrong.

I happen to have discovered a direct relation between magnetism and light, also electricity and light, and the field it opens is so large and I think rich.

Speculations? I have none. I am resting on certainties.