The illusion that we are separate from one another is an optical delusion of our consciousness.

Though our conduct seems so very different from that of the higher animals, the primary instincts are much alike in them and in us.

The world is not threatened by evil people, but by those who allow evil to take place.

The world is an evil place to live in. Not for those who do evil, but for those who sit back and allow evil to occur.

But if the longing for the achievement of the goal is powerfully alive within us, then shall we not lack the strength to find the means for reaching the goal and for translating it into deeds.

One must shy away from questionable undertakings, even when they bear a high-sounding name.

All our thoughts and concepts are called up by sense-experiences and have a meaning only in reference to these sense-experiences. On the other hand, however, they are products of the spontaneous activity of our minds; they are thus in no wise logical consequences of the contents of these sense-experiences. If, therefore, we wish to grasp the essence of a complex of abstract notions we must for the one part investigate the mutual relationships between the concepts and the assertions made about them; for the other, we must investigate how they are related to the experiences.