Descartes. In his principles, the more solid a body is, the more its parts are at rest in relation to one another. — He would have done better to advise us to examine all our opinions as obscure than as false.

Two philosophies. One cried: Distrust your senses. The other came: Distrust your mind if it speaks otherwise than your senses.

April 1.

Everything is play except what makes the soul better or worse.

Children who plant flowers by their stems. — Institutions must spring from customs. Institutions need soil already prepared.

April 2.

In the ode, the poet must surely be allowed, for rest and relaxation, the pleasure of speaking of himself.

There are truths that may instruct, but do not illuminate. And all truths of reasoning are of this kind.

April 4.

Theories have caused more experiments than experiments have caused theories. This shows how useful what is purely rational in each science is to the progress of the arts.

The ancients said, “matter does not love the void.” This was how they expressed, but did not explain, some of the phenomena of gravitation.

Holy Monday, April 7. At Le Chaylard.

What Socrates says of greatness in the Phaedo is exact if one confines it to moral things; and common speech accords with it. One could very well say, “there is greatness in this project, there is beauty in this thought,” and one could not say, “there is beauty in this snuffbox,” although one says that a snuffbox is beautiful; “there is greatness in this stick,” although one says a large stick.

Whatever one may claim to the contrary, what can be measured and assessed only by thought (that is, everything intellectual) can be measured, judged, assessed only by a secret comparison with an ideal model placed in our head without our knowing it. In all these instances, there is some idea in us that, without our knowing it, serves us as a weight, a gauge, a standard, etc. Material things, on the contrary, are assessed by measures of the same nature, and nothing physical can consequently be called small or large, beautiful or misshapen, except in a physically relative way. Socrates is wrong when he claims that everything is beautiful or great only insofar as it partakes of greatness, of beauty. The word everything must be confined to those things that cannot strike the senses. And then these words greatness and beauty may be understood as an absolute greatness and beauty, such as they exist in God or in the idea God has of them.

April […].

Virtue cannot be learned (says Plato). But piety, which gives it, can be learned. Oh ubi pietas, says the poet. What there is of the material, the mechanical, and the properly human can be taught and learned by human means, but what is divine in it can be communicated only through a divine intervention, I mean through ideas, feelings whose object is the gods themselves.

Algebraic formulas outside algebra. — Are only abbreviations. And one can even say that they are to the mind what the abbreviations of the Greek language are to the eyes: sometimes convenient but always unpleasant; convenient for the author, for the writer, for the printer, unpleasant to everyone else.

April 10.

Voltaire says that “remorse is an affection nature gives us.” As it gives us all the others. This is admirable.

In their impatience, these clear minds discover more truths in an instant than slow minds can in years and centuries in the coldness of their studies.