If you have a room which you do not want certain people to get into, put a lock on it for which they do not have the key. But there is no point in talking to them about it, unless of course you want them to admire the room from outside! The honorable thing to do is put a lock on the door which will be noticed only by those who can open it, not by the rest.

An honest religious thinker is like a tightrope walker. He almost looks as though he were walking on nothing but air. His support is the slenderest imaginable. And yet it really is possible to walk on it.

But doesn't it come out here that knowledge is related to a decision?

Anything your reader can do for himself leave to him.

Don't think, but look! (PI 66)

What is the proof that I know something? Most certainly not my saying I know it.

All testing, all confirmation and disconfirmation of a hypothesis takes place already within a system. And this system is not a more or less arbitrary and doubtful point of departure for all our arguments: no, it belongs to the essence of what we call an argument. The system is not so much as the point of departure, as the element in which arguments have their life.

It is difficult to describe paths of thought where there are already many paths laid down, and not fall into one of the grooves

At the basis of the whole modern view of the world lies the illusion that the so-called laws of nature are the explanations of natural phenomena. So people stop short at natural laws as at something unassailable, as did the ancients at God and Fate.And they both are right and wrong. But the ancients were clearer, in so far as they recognized one clear conclusion, whereas in the modern system it should appear as though everything were explained.