You can alter your life by altering the state of your mind.

The 'I think' which Kant said must be able to accompany all my objects, is the 'I breathe' which actually does accompany them.

When a superior intellect and a psychopathic temperament coalesce in the same individual, we have the best possible condition for the kind of effective genius that gets into the biographical dictionaries.

It is well for the world that in most of us, by the age of thirty, the character has set like plaster, and will never soften again.

The total mental efficiency of a man is the resultant of the working together of all his faculties. He is too complex a being for any one of them to have the casting vote. If any one of them do have the casting vote, it is more likely to be the strength of his desire and passion, the strength of the interest he takes in what is proposed. Concentration, memory, reasoning power, inventiveness, excellence of the senses, all are subsidiary to this.

Truth is what will be steadily borne out by subsequent experience

Science as such assuredly has no authority, for she can only say what is, not what is not.