Possibilities are like the wings of birds; they allow man to soar and to climb to the heavens. And facts are like the atmosphere against which those wings must beat, and without which the soaring bird will surely plummet back to earth.

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.

Learn, compare, collect the facts!

Learn the ABC of science before you try to ascend to its summit.

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.

I am convinced that an important stage of human thought will have been reached when the physiological and the psychological, the objective and the subjective, are actually united, when the tormenting conflicts or contradictions between my consciousness and my body will have been factually resolved or discarded.

Gradualness, gradualness, and gradualness. From the very beginning of your work, school yourself to severe gradualness in the accumulation of knowledge.