Whatever we know without inference is mental.

Many a marriage hardly differs from prostitution, except being harder to escape from.

A hallucination is a fact, not an error; what is erroneous is a judgment based upon it.

There are some simple maxims which I think might be commended to writers of expository prose. First: never use a long word if a short word will do. So, if you want to make a statement with a great many qualifications, put some of the qualifications in separate sentences. Third: do not let the beginning of your sentence lead the reader to an expectation which is contradicted by the end.

The fact that all Mathematics is Symbolic Logic is one of the greatest discoveries of our age; and when this fact has been established, the remainder of the principles of mathematics consists of the analysis of Symbolic Logic itself.

The saviors of the world, society's last hope.

A habit of basing convictions upon evidence, and of giving to them only that degree or certainty which the evidence warrants, would, if it became general, cure most of the ills from which the world suffers.