sity is there, for example, of explaining what is understood by the word man? Do we not know well enough what the thing is that we wish to designate by this term? And what advantage did Plato think to procure us in saying that he was a two-legged animal without feathers? As though the idea that I have of him naturally, and which I cannot express, were not clearer and surer than that which he gives me by his useless and even ridiculous explanation; since a man does not lose humanity by losing the two legs, nor does a capon acquire it by losing his feathers.
There are those who are absurd enough to explain a word by the word itself. I know some who have defined light in this wise: Light is a luminary movement of luminous bodies, as though we could understand the words luminary and luminous without the word light.[1]
We cannot undertake to define being without falling into the same absurdity: for we cannot define a word without beginning with the word it is, either expressed or understood. To define being therefore, it is necessary to say it is, and thus to employ the word defined in the definition.
We see clearly enough from this that there are some words incapable of being defined; and, if nature had not supplied this defect by a corresponding idea which she has given to all mankind, all our expressions would be confused; whilst we use them with the same assurance and the same certainty as though they were explained in a manner perfectly exempt from ambiguities; because nature herself has given us, without words, a clearer knowledge of them than art could acquire by our explanations.
It is not because all men have the same idea of the essence of the things that I say that it is impossible and useless to define.
For, for example, time is of this sort. Who can define it?
- ↑ Pascal alludes here to Father Noël, a Jesuit, with whom he had had a warm discussion on the subject of his Expériences touchant le vide. In a letter that he wrote to Father Noël in 1647, he said: "The sentence which precedes your closing compliments defines light in these terms: Light is a luminous motion of rays composed of lucid, that is, luminous bodies; upon which, I have to tell you that it seems to me that you ought first to have defined what luminous is, and what a lucid or luminous body is, for till then, I cannot understand what light is. And as we never make use in definitions of the term of the thing defined, I should have difficulty in conforming to yours which says: Light is a luminary motion of a luminous body."—Faugère.
