A man may imagine things that are false, but he can only understand things that are true, for if the things be false, the apprehension of them is not understanding.

Hypotheses should be subservient only in explaining the properties of things but not assumed in determining them, unless so far as they may furnish experiments.

As a blind man has no idea of colors, so have we no idea of the manner by which the all-wise God perceives and understands all things.

The proper method for inquiring after the properties of things is to deduce them from experiments.

We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances.

It may be that there is no such thing as an equable motion, whereby time may be accurately measured. All motions may be accelerated or retarded, but the true, or equable, progress of absolute time is liable to no change.