A lunatic is just a minority of one.

We realize we can't go around saying and doing what we're actually thinking and feeling. If we all did that, life would be a lunatic asylum. Indeed, that's how you know you're talking to a lunatic. Lunatics are those poor souls who have lost their inner communication and so they allow themselves to say and do exactly what they are thinking and feeling and that's why they're mad.

Perhaps a lunatic was simply a minority of one.

The lunatic is all idée fixe, and whatever he comes across confirms his lunacy. You can tell him by the liberties he takes with common sense, by his flashes of inspiration, and by the fact that sooner or later he brings up the Templars.

The difference between a humanist and a lunatic is in fact one of degree

There are four kinds of people in this world: cretins, fools, morons, and lunatics…Cretins don’t even talk; they sort of slobber and stumble…Fools are in great demand, especially on social occasions. They embarrass everyone but provide material for conversation…Fools don’t claim that cats bark, but they talk about cats when everyone else is talking about dogs. They offend all the rules of conversation, and when they really offend, they’re magnificent…Morons never do the wrong thing. They get their reasoning wrong. Like the fellow who says that all dogs are pets and all dogs bark, and cats are pets, too, therefore cats bark…Morons will occasionally say something that’s right, but they say it for the wrong reason…A lunatic is easily recognized. He is a moron who doesn’t know the ropes. The moron proves his thesis; he has logic, however twisted it may be. The lunatic on the other hand, doesn’t concern himself at all with logic; he works by short circuits. For him, everything proves everything else. The lunatic is all idée fixe, and whatever he comes across confirms his lunacy. You can tell him by the liberties he takes with common sense, by his flashes of inspiration, and by the fact that sooner or later he brings up the Templars…There are lunatics who don’t bring up the Templars, but those who do are the most insidious. At first they seem normal, then all of a sudden…

The ordinary lunatic is generally a harmless, isolated case; since everyone sees that something is wrong with him, he is quickly taken care of. But the unconscious infections of groups of so-called normal people are more subtle and far more dangerous.

There are always some lunatics about. It would be a dull world without them.

Dispute not with her: she is lunatic.

But the thought of being a lunatic did not greatly trouble him; the horror was that he might also be wrong.

Strange times are these in which we live when old and young are taught falsehoods in school. And the person that dares to tell the truth is called at once a lunatic and fool

She didn't quite know what the relationship was between lunatics and the moon, but it must be a strong one, if they used a word like that to describe the insane.

All are lunatics, but he who can analyze his delusion is called a philosopher.

Man is so intelligent that he feels impelled to invent theories to account for what happens in the world. Unfortunately, he is not quite intelligent enough, in most cases, to find correct explanations. So that when he acts on his theories, he behaves very often like a lunatic.