The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.

Within the last fifty years, the extraordinary growth of every department of physical science has spread among us mental food of so nutritious and stimulating a character that a new ecdysis seems imminent.

The great thing in the world is not so much to seek happiness as to earn peace and self-respect.

What men of science want is only a fair day's wages for more than a fair day's work.

I took thought, and invented what I conceived to be the appropriate title of 'agnostic'.

In fact a favourite problem of Tyndall is-Given the molecular forces in a mutton chop, deduce Hamlet or Faust therefrom. He is confident that the Physics of the Future will solve this easily.

I protest that if some great Power would agree to make me always think what is true and do what is right, on condition of being turned into a sort of clock and would up every morning before I got out of bed, I should instantly close with the offer.