You will certainly not doubt the necessity of studying astronomy and physics, if you are desirous of comprehending the relation between the world and Providence as it is in reality, and not according to imagination.

Be convinced that, if man were able to reach the end without preparatory studies, such studies would not be preparatory but tiresome and utterly superfluous.

No disease that can be treated by diet should be treated with any other means.

Nobody is ever impoverished through the giving of charity.

You must consider, when reading this treatise, that mental perception, because connected with matter, is subject to conditions similar to those to which physical perception is subject.

The same is the case with those opinions of man to which he has been accustomed from his youth; he likes them, defends them, and shuns the opposite views.

In the beginning we must simplify the subject, thus unavoidably falsifying it, and later we must sophisticate away the falsely simple beginning.