II. The Logic of Thought and the Logic of Reality

This is what Mach says to himself, every now and then when he withdraws a little from these things and considers them again. You will find it in his books. And he then makes a peculiar remark; he says: sometimes one has a feeling that makes one ask:—Can it be that we human beings are just being led round and round in a circle by some evil spirit? And he answers: Sometimes I really think so.