Necessity is the mistress and guide of nature. Necessity is the theme and inventress of nature, her curb and her eternal law.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.

Nature never breaks her own laws.

Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from this to proceed to investigate the reason.

Nature is full of infinite causes that have never occurred in experience.

Nature never breaks her own laws