Science is practical philosophy.

When writing about transcendental issues, be transcendentally clear.

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

It is possible that I am dreaming right now and that all of my perceptions are false.

... moral certainty is certainty which is sufficient to regulate our behaviour, or which measures up to the certainty we have on matters relating to the conduct of life which we never normally doubt, though we know that it is possible, absolutely speaking, that they may be false.

Except our own thoughts, there is nothing absolutely in our power.

The chief cause of human errors is to be found in the prejudices picked up in childhood.