Mathematics is a more powerful instrument of knowledge than any other that has been bequeathed to us by human agency.

There is nothing so strange and so unbelievable that it has not been said by one philosopher or another.

My third maxim was to try always to conquer myself rather than fortune, and to change my desires rather than the order of the world, and generally to accustom myself to believing that there is nothing entirely in our power except our thoughts, so that after we have done our best regarding things external to us, everything in which we do not succeed is for us absolutely impossible.

And thereby make ourselves, as it were, the lords and masters of nature.

The rainbow is such a remarkable phenomenon of nature, and its cause has been so meticulously sought after by inquiring minds throughout the ages, that I could not choose a more appropriate subject for demonstrating how, with the method I am using, we can arrive at knowledge not possessed at all by those whose writings are available to us.

But possibly I am something more than I suppose myself to be.

There is a great difference between mind and body insomuch as body is by nature always divisible, and the mind is entirely indivisible.