1: Rules of Reasoning

Book 1 laid down the principles of mathematical philosophy. This will be the basis of our reasonings on philosophical inquiries.

These mathematical principles are the laws and conditions of certain motions and forces. I use them to build a system of the universe.

To prevent them from being dry and barren, I have illustrated them here with some philosophical scholiums, such as:

• the density and the resistance of bodies
• spaces void of all bodies and
• the motion of light and sounds.

I explain the principles as propositions. Readers should go through Books 1 and 2 first, specifically:

• the definitions
• laws of motion
• sections 1-3 of Book 1

Rules Of Reasoning

Rule 1: We only need to look for the causes of natural phenomena that are enough to explain their appearances.

Nature is pleased with simpicity.

Rule 2: The same natural effects come from the same natural causes

• Respiration is the same for humans and animals
• The light of our stove fire is the same as the light of the sun

Rule 3(!*): Universal qualities are those which are common to all the bodies which we experiment with

The qualities of bodies are only known to us by experiments. We deem universal all those qualities that universally agree with experiments.

We will not relinquish the evidence of experiments for the sake of vain fictions.

We can only know bodies by our senses.

Rule 4*: Induction from Phenomena over Imaginary Hypothesis

Our experiments, must be based on propositions collected by general induction from phenomena as accurately or very nearly true, despite any contrary imaginary hypotheses, until these are corrected by other phenomena. The argument of induction cannot evaded by hypotheses.