Notes on Aristotle’s “Physics”

Book I

Physics studies the causes and principles of natural beings.

“Cause” and “principles” defined:

I just skimmed over Book I, and have taken note of the most interesting parts of it. I would prefer to focus on Book II. Because of this, I recommend that you skip straight to “Book II – What is nature?” below.

Q: How many elements are there, Aristotle?
A: Either two or three.

This is one of the many parts of the Physics that are primarily of historical value; if you can restate the arguments found here in a modern form, that would be great. But this chapter is mostly of interest in the way he goes about getting his answers.

“The principles in question must be either (a) one or (b) more than one. If (a) one, it must be either (i) motionless, as Parmenides and Melissus assert, or (ii) in motion, as the physicists hold, some declaring air to be the first principle, others water. If (b) more than one, then either (i) a finite or (ii) an infinite plurality. If (i) finite (but more than one), then either two or three or four or some other number. If (ii) infinite, then either as Democritus believed one in kind, but differing in shape or form; or different in kind and even contrary.” (Physics I.2)

Number of Principles

  1. One
    1. Motionless – Don’t even bother with these people.
    2. In motion
      1. Urstoff
      2. Tao
  2. Many
    1. Finite in number
      1. 2 in number
        1. Yin/Yang
        2. Matter and Spirit
        3. Matter and Energy
        4. Temperature, Moisture (Aristotle)
      2. 3 in number
        1. Sattvas, Rajas, Tamas (Bhagavad Gita)
        2. Tripartite soul (Plato)
      3. 4 in number
        1. Earth, Air, Fire, Water
      4. or more
        1. Five Elements of TCM
        2. Four Elements plus Spirit – India, elsewhere
    2. Infinite in number
      1. Same or differ only in form – Atomism
      2. Contrary or Differ in kind


The Elements and the Categories

First, he looks at the idea that “All is One.” This thesis was defended by many Greek thinkers, both naturalistic and otherwise. Aristotle attacks both at once using his doctrine of Categories, which can be found in his book Categories I.4, and is not merely an exercise in logic-chopping; the most masterful use of it is in the Nicomachean Ethics I.6, where he uses it to destroy Plato’s ethical theory as well as the possibility of the “Philosopher King”.

A “category” is a way that one can use the verb “to be., as in the following:

substance- “Lassie is a dog.”

quantity- “There are seven days in the week.”

quality- “The sky is blue.”

relation- “Plato was older that Aristotle. ”

place- “I am here.”

time- “This is now.”

position, state, action,  affection, etc.- and so on and so forth; there could be an infinite number of categories, the key thing is that if you are saying “All is One.”, which category of “is” are you using? I fail to say how we can know if all is one or not if we do not know what the “is” means.

Somehow I still think that “All is One” in the sense that we are all made of the same stuff, but have different forms. Aristotle seems to think that there are either two or three “elements”, and he prefers two elements “hot/cold” and “dry/wet”, which then combine to form the Four Elements of Fire, Air, Water and Earth.

I and most modern physicists seem to think that there simply has to be one underlying stuff out of which matter, energy, space, time, whatever all come. But once you read his use of the categories in other contexts, you will have lots of respect for it. In fact, it is one of the thinks where he really anticipates modern ideas of information useful in software.

Book II

Section 1

What is nature?

“Nature” (Grk. phusis) – a principle of change in itself and not in an other.


  • Animals
  • Plants
  • “Simple bodies” –  The Four Elements: Earth, Air, Fire, Water

All of these has in itself its own principle of change or of staying unchanged.

  • Movement, Holding still
  • Growth
  • Decay
  • Alteration

A bed or a coat has no innate principle qua product of skill or art (Grk. tekne).However, the matter from which it is made is still natural, and thus has its own principle of change within it qua natural material. This means that if a wooden bed could grow, it would sprout a tree, not another bed. The natural movement of the bed is to fall if dropped, not to move about and grow into a full-sized bed. Falling is the natural movement of its matter, not due to its artificial form. Living creatures, on the other hand have natural movement specific to their forms. Snails and octopi are similar in matter, but not in form, and their form determines their natural behavior. But wooden furniture all behaves the same way which depends only on how they are used by others.

The bed is natural as matter, but not as bed (form). The form comes from  the craftsman, not the matter itself.

Both phusis and tekne are principles of change, but phusis is self-change.

A doctor uses tekne to heal an other, but natural healing is when the body heals itself. On occasion, doctors may treat themselves, but this is still not “natural” (kata phusis – “according to nature).  On the contrary, natural healing can never heal an other. This is even more clearly true of the skills of carpentry, masonry, sculpture, painting, et cetera.

[Another difference between nature and skill is that skill can also be used to create the opposite effect, for example a doctor can use their knowledge to kill or harm. The body’s natural healing powers can never be used to cause harm. See Metaphysics Book VII]

Various conceptions of “nature”.

Phusis as Matter (193.10)

Some believe that the nature of a thing is its matter, since the matter was there prior to form. For composite materials (“compounds”), the nature of the compound is derived from the nature of the simple elements that form the compound.

Some materialists have chosen one of the simple elements for the role of fundamental element. (E.g. Thales “All is Water.”)

Phusis as Form  (193.30)

Another way of defining nature is “the form which accords with its logos.”

“Men (anthropoi) come from men.” – Natural beings contain their own forms.
“Beds do not come from beds.” – Artificial beings do not contain their own form.

Phusis as Telos (193.15)

Art does not produce art. Medicine produces health, not medicine.

Nature produces nature. Humans produce humans.

Is this true? -“The telos of nature is to produce the form, and the telos of the form is to manifest proper activity.” (This is just me talking, not Aristotle.)

Section 2 – Nature and Mathematics

How natural or unnatural is mathematics?

Section 3 – The Four Causes

Material Causes

Formal Causes

Efficient Causes

Telos – “Final causes”


Section 4 – Chance and Automaton.

Section 5 – What is luck (tyche)?


Section 7- What are causes?

Section 8 – Telos: Natural and Artificial.

Section 9 – Nature and Necessity

Other treatments concerning nature and tekne in Aristotle.

Metaphysics V: Definitions of

Section 1: arkhe – “principle”, “beginning”, “leader”

Section 2:  aitia – “causes”, “exlanations”

Section 3: stoicheia – “elements”

Section 4: phusis – “nature”

Metaphysics VII, 7-9: Natural and artificial “powers” or abilites.

On the Soul I.1ff – Focuses on living natural beings.

Nicomachean Ethics I.1ff – “What is the telos of life?” Focuses on natural living human beings.


One thought on “Notes on Aristotle’s “Physics”

  1. Pingback: Notes on Aristotle’s “Metaphysics” Book I – Zoon Echon Blogon

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