Science without religion is lame. Religion without science is blind.

The great variability of all the external differences between the races of man, likewise indicates that they cannot be of much importance; for if important, they would long ago have been either fixed and preserved, or eliminated.

Man is an animal with primary instincts of survival. Consequently, his ingenuity has developed first and his soul afterwards. The progress of science is far ahead of man's ethical behavior.

The wise man should restrain his senses like the crane and accomplish his purpose with due knowledge of his place, time and ability.

Natural science will in time incorporate into itself the science of man, just as the science of man will incorporate into itself natural science: there will be one science.

The man of science is a poor philosopher.