All definite knowledge - so I should contend - belongs to science; all dogma as to what surpasses definite knowledge belongs to theology. But between theology and science there is a No Man's Land, exposed to attack by both sides; this No Man's Land is philosophy.

It has been said that man is a rational animal. All my life I have been searching for evidence which could support this.

Ideas and principles that do harm are as a rule, though not always, cloaks for evil passions.

It will be said that the joy of mental adventure must be rare, that there are few who can appreciate it, and that ordinary education can take no account of so aristocratic a good. I do not believe this. The joy of mental adventure is far commoner in the young than in grown men and women. ...It is rare in later life because everything is done to kill it during education.

Every increase in knowledge requires an increase in wisdom

The opposition of instinct and reason is mainly illusory. Instinct, intuition, or insight is what first leads to the beliefs which subsequent reason confirms or confutes; but the confirmation, where it is possible, consists, in the last analysis, of agreement with other beliefs no less instinctive. Reason is a harmonizing, controlling force rather than a creative one. Even in the most purely logical realms, it is insight that first arrives at what is new.

The fundamental defect of fathers, in our competitive society, is that they want their children to be a credit to them. We all feel instinctively, that our children's success reflect glory upon ourselves, while their failures make us feel shame. Unfortunately, the successes which cause us to swell with pride are often of an undesirable kind.... Neither happiness nor virtue, but worldly success, is what the average father desires for his children.