心理学的真理是在现实世界中有效的东西。
Psychological truth is what works in the practical world.
The study of truth requires a considerable effort - which is why few are willing to undertake it out of love of knowledge - despite the fact that God has implanted a natural appetite for such knowledge in the minds of men.
事物的变化是其本质特征,适应变化是智慧。