The greatest marvel is not in the individual. It is in the succession, in the renewal and in the duration of the species that Nature would seem quite inconceivable. This power of producing its likeness that resides in animals and plants, this form of unity, always subsisting and appearing eternal, this procreative virtue which is perpetually expressed without ever being destroyed, is for us a mystery which, it seems, we will never be able to fathom.

The greatest marvel is not in the individual. It is in the succession, in the renewal and in the duration of the species that Nature would seem quite inconceivable. This power of producing its likeness that resides in animals and plants, this form of unity, always subsisting and appearing eternal, this procreative virtue which is perpetually expressed without ever being destroyed, is for us a mystery which, it seems, we will never be able to fathom.

There is nothing good in love but the physical part.

Nature is the system of laws established by the Creator for the existence of things and for the succession of creatures. Nature is not a thing, because this thing would be everything. Nature is not a creature, because this creature would be God. But one can consider it as an immense vital power, which encompasses all, which animates all, and which, subordinated to the power of the first Being, has begun to act only by his order, and still acts only by his concourse or consent ... Time, space and matter are its means, the universe its object, motion and life its goal.

As historians, we refuse to allow ourselves these vain speculations which turn on possibilities that, in order to be reduced to actuality, suppose an overturning of the Universe, in which our globe, like a speck of abandoned matter, escapes our vision and is no longer an object worthy of our regard. In order to fix our vision, it is necessary to take it such as it is, to observe well all parts of it, and by indications infer from the present to the past.

Genius is only a greater aptitude for patience.

The discoveries that one can make with the microscope amount to very little, for one sees with the mind's eye and without the microscope the real existence of all these little beings.