Never think that you already know all. However highly you are appraised, always have the courage to say to yourself-I am ignorant.

Don't become a mere recorder of facts, but try to penetrate the mystery of their origin.

When the dog is repeatedly teased with the sight of objects inducing salivary secretion from a distance, the reaction of the salivary glands grows weaker and weaker and finally drops to zero.

Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching.

While you are experimenting, do not remain content with the surface of things.

Men are apt to be much more influenced by words than by the actual facts of the surrounding reality

Perfect as the wing of a bird may be, it will never enable the bird to fly if unsupported by the air. Facts are the air of science. Without them a man of science can never rise.

Appetite, craving for food, is a constant and powerful stimulator of the gastric glands.

It is still open to question whether psychology is a natural science, or whether it can be regarded as a science at all.

Perfect as the wing of a bird may be, it will never enable the bird to fly.

School yourself to demureness and patience. Learn to inure yourself to drudgery in science. Learn, compare, collect the facts.

Religious people fear hell -- Spiritual people have walked thru it.

Our sacrosanct obligation is to tend to our own personal wounds and furiously love the entire world irrespective if the world loves us back.

Freedom is secured not by the fulfilling of men's desires, but by the removal of desire.

Power is defined as an ability to do qualitative work with a quantitative passion, backed by a compelling conviction, directed by a propelling purpose, fulfilling a divine destiny. That is power!

Grown up, and that is a terribly hard thing to do. It is much easier to skip it and go from one childhood to another.

Never get satisfied. The minute you stop trying, you go downhill.

Only the heart without a stain knows perfect ease. [Ger., Ganz unbefleckt geniesst sich nur das Herz.]

The single most loving act we can do is share the good news of Jesus Christ, that God saves sinners.

Big game photography in Africa is mainly done from a vehicle, so then I feel I might as well take the lot.

A vacant white room with lights is still a submission to the neutral. Works of art seen in such spaces seem to be going through a kind of esthetic convalescence.