As we can not give a general definition of energy, the principle of the conservation of energy signifies simply that there is something which remains… - Henri Poincaré

The readings we shall be able to make on our instruments at any instant will depend only on the readings we could have made on these same instruments at the initial instant.

[I]t is the sidereal day, that is, the duration of the rotation of the earth, which is the constant unit of time. ...However ...[many] astronomers ...think that the tides act as a check on our globe, and that the rotation of the earth is becoming slower and slower. Thus would be explained the apparent acceleration of the motion of the moon...

What is zero? It is the number of elements in the class nil. And what is the class nil? It is the class which contains none.
To define zero as nil and nil as none is really an abuse of the wealth of language, and so [Logicists] introduced an improvement into the definition, ... which means in English: zero is the number of the objects that satisfy a condition that is never fulfilled. But as never means in no case, I do not see that any very great progress has been made.