No human investigation can be called real science if it cannot be demonstrated mathematically.

How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!

I think men of science as well as other men need to learn from Christ, and I think Christians whose minds are scientific are bound to study science that their view of the glory of God may be as extensive as their being is capable.

Freedom of thought is best promoted by the gradual illumination of men's minds which follows from the advance of science.

If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find no such case.

It is inconceivable that inanimate brute matter should, without the mediation of something else which is not material, operate upon and affect other matter without mutual contact, as it must be, if gravitation in the sense of Epicurus, be essential and inherent in it. And this is one reason why I desired you would not ascribe innate gravity to me.