From their experience or from the recorded experience of others (history), men learn only what their passions and their metaphysical prejudices allow them to learn.

Every notable advance in technique or organization has to be paid for, and in most cases the debit is more or less equivalent to the credit. Except of course when it's more than equivalent, as it has been with universal education, for example, or wireless, or these damned aeroplanes. In which case, of course, your progress is a step backwards and downwards.

The only consistent people are the dead

The world is an illusion, but an illusion which we must take seriously.

Every ceiling reached becomes a floor.

This really revolutionary revolution is to be achieved, not in the external world, but in the souls and flesh of human beings.

Of the significant and pleasurable experiences of life only the simplest are open indiscriminately to all. The rest cannot be had except by those who have undergone a suitable training.