The method of psychology must be as exact as the methods of the natural sciences.

The human heart, at whatever age, opens only to the heart that opens in return.

对上帝的观念越强大和生动，它将越影响我们的生活和性格。

真正的科学进步不是通过简单的事实积累实现的，而是通过理论和模型的不断精炼。