It sounds paradoxical to say the attainment of scientific truth has been effected, to a great extent, by the help of scientific errors.

I have endeavoured to show that no absolute structural line of demarcation, wider than that between the animals which immediately succeed us in the scale, can be drawn between the animal world and ourselves; and I may add the expression of my belief that the attempt to draw a physical distinction is equally futile, and that even the highest faculties of feeling and of intellect begin to germinate in lower forms of life.

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.

[Scientists] have learned to respect nothing but evidence, and to believe that their highest duty lies in submitting to it however it may jar against their inclinations.

Ecclesiasticism in science is only unfaithfulness to truth

Better live a crossing-sweeper than die and be made to talk twaddle by a "medium" hired at a guinea a seance.

It is wrong for a man to say that he is certain of the objective truth of any proposition unless he can produce evidence which logically justifies that certainty. This is what Agnosticism asserts; and, in my opinion, it is all that is essential to Agnosticism. That which Agnostics deny and repudiate, as immoral, is the contrary doctrine, that there are propositions which men ought to believe without logically satisfactory evidence; and that reprobation ought to attach to the profession of disbelief in such inadequately supported propositions.