The Philosophy of Democritus

²⁰² The philosophy of Democritus is not less different from ours than from the common.

[Footnote: “that of Aristotle or the others.”]

But Democritus also supposed certain corpuscles that were of various shapes, sizes, and motions, from the heaping together and mutual concourse of which all sensible bodies arose.

Nevertheless, his mode of philosophizing is commonly rejected by all.

I reply that the philosophy of Democritus was never rejected by anyone, because he allowed the existence of bodies smaller than those we perceive, and attributed to them diverse sizes, figures, and motions, for no one can doubt that there are in reality such, as we have already shown;

The philosophy of Democritus was rejected because:

1. He supposed that these corpuscles were indivisible.

   • I also reject this

2. He imagined there was a vacuum about them

   • I show that this is impossible

3. He attributed gravity to these bodies, of which I deny the existence in any body, in so far as a body is considered by itself, because it is a quality that depends on the relations of situation and motion which several bodies bear to each other

4. He did not explain how all things arose from the concourse of corpuscles alone

²⁰³ How we may know the shapes, [magnitudes], and motions of the insensible particles?

I assign determinate shapes, magnitudes, and motions to the insensible particles of bodies, as if I had seen them.

First, I considered in general all our clear notions of material things that are to be found in our understanding.

I only found the shapes, magnitudes, and motions, and rules which are the principles of geometry and mechanics.

I judged that all the knowledge man can have of nature must necessarily be drawn from the principles of geometry and mechanics.

This is because all the other notions we have of sensible things, as confused and obscure, cannot bring us knowledge but rather impedes knowledge.

Thereupon, taking as my ground of inference the simplest and best known of the principles that have been implanted in our minds by nature, I considered the chief differences that could possibly subsist between:

• the magnitudes, shapes, and situations of bodies insensible because of their smallness alone, and
• what sensible effects could be produced by our contact with them

I found like effects in the bodies that we perceive by our senses. From this, I judged that they could have been thus produced, especially since no other mode of explaining them could be devised.

In this way, the example of several bodies made by art was of great service to me.

I see no difference between these and natural bodies beyond this, that the effects of machines depend for the most part on the agency of certain instruments, which, as they must bear some proportion to the hands of those who make them, are always so large that their figures and motions can be seen;

in place of which, the effects of natural bodies almost always depend upon certain organs so minute as to escape our senses.

All the rules of mechanics belong also to physics.

• A clock, made of the needed number of wheels, marks the hours naturally.
• This is the same as a tree, which has sprung from seed, to produce the fruit peculiar to it.

When we learn how a machine works and see some of its parts, we easily infer from these how their unseen parts work as well.

In the same way, I have written about the character and causes of the insensible parts of natural bodies.

²⁰⁴ Touching the things which our senses do not perceive, it is sufficient to explain how they can be, [and that this is all that Aristotle has essayed].

But here some one will perhaps reply, that although

I have supposed causes which could produce all natural objects. But we should not conclude that they were produced by these causes.

An artisan can make 2 clocks that are both accurate and have the same outward appearance, even if their internal mechanism is different.

Likewise, the Supreme Maker of things has an infinity of diverse means at his disposal to make all the existing things that we see. But it is impossible for the human mind to know which of all these means he chose to employ.

I most freely concede this.

I believe that I have done all that was required, if the causes I have assigned are such that their effects accurately correspond to all the phenomena of nature, without determining whether it is by these or by others that they are actually produced.

And it will be sufficient for the use of life to know the causes thus imagined, for medicine, mechanics, and in general all the arts to which the knowledge of physics is of service, have for their end only those effects that are sensible, and that are accordingly to be reckoned among the phenomena of nature.

[Footnote: “have for their end only to apply certain sensible bodies to each other in such a way that, in the course of natural causes, certain sensible effects may be produced; and we will be able to accomplish this quite as well by considering the series of certain causes thus imagined, although false, as if they were the true, since this series is supposed similar as far as regards sensible effects."-French.]

In Book 1 Chapter 7 of Meteorologies, Aristotle adduces sufficient reasons and demonstrations of things which are not manifest to the senses.

²⁰⁵ There is a moral certainty that all the things are such as has been here shown they may be.

There are 2 kinds of certitude:

1. Moral

This is a certainty sufficient for the conduct of life even if it might be false from God’s point of view.

For example, those who have never visited Rome do not doubt that it is a city of Italy.

2. Absolute

This is certainty from God’s point of view.

Let’s say a person wrote a letter using a reversed alphabet where z is a and a is z. In this case, the letter would be unreadable to a person who did not use the reverse alphabet. It would be morally uncertain.

But it would be readable to someone who used a reverse alphabet. It would have absolute certainty after conversion.

The phenomena regarding the magnet, fire, and the fabric of the whole world, are here deduced from very few principles. The coherence of these phenomena prove that these principles are true.

²⁰⁶ We possess even more than a moral certainty of it.

There are some, even among natural, things which we judge to be absolutely certain. [Absolute certainty arises when we judge that it is impossible a thing can be otherwise than as we think it].

This certainty is founded on the metaphysical ground, from the fact that God is supremely good and the source of all truth.

• He gave us the faculty of distinguishing truth from error.
• This faculty cannot be fallacious so long as we:
  • use it correctly
  • distinctly perceive anything by it.

Of this character are:

• the demonstrations of mathematics
• the knowledge that material things exist
• the clear reasonings that are formed regarding them.

My results in this treatise will perhaps be admitted as part of the class of truths that are absolutely certain.

• This will happen if it they are deduced in a continuous series from the first and most elementary principles of human knowledge
• This is if people understand that we can only perceive external objects if they cause some local motion in our nerves.

Such motion cannot be caused by the fixed stars unless those stars produce a motion in our nerves and in the whole heavens between them and us.

Remove those stars, then my general doctrines regarding the world or earth [e. g., the fluidity of the heavens, Part 3, Section 46] are the only explanations of the phenomena they present.