- Melissus (mid 5th Century BCE)
"And it cannot perish, or become greater,
or be rearranged, or feel pain or distress. For if it experienced any of these,
it would no longer be one. For if it became different, it is necessary that
what is is not alike, but what previously was perishes, and what is not comes
to be." (Trans. Richard McKirahan, Philosophy Before Socrates, 1994
Hackett Pub Co.)
How can I change from hungry to full or a
tomato change from green to red; if something truly changes then it is different
at the end, but if it is different then how any one thing have changed? Change
requires me or the tomato to be both the same (thing) and different at the
end.
- More precisely, if X is Z and Y is Z' and Z is not Z', then X is not Y:
- e.g., Bush is the President of the USA and Putin is the President of Russia and Bush is not Putin, then the President of the USA is not the President of Russia.
- similarly, if the tomato yesterday is green and the tomato tomorrow is red, then since red is not green, the tomato yesterday is not the tomato tomorrow – so how can we say that the tomato changed!
- Worse, if X is Z and Y is Z' and Z is Z', then X is Y:
- The newest reporter for the Daily Planet is Clark Kent and Superman is Clark Kent, so (since Clark Kent is Clark Kent) the newest reporter for the Daily Planet is Superman.
- similarly, I am real, and the tomato is real, and you are real,
and the table is real, and Bush is real and so on for everything in the universe
– but if everything is real, then everything is everything else! There is
only one thing – reality.
"It is clear, then, that we did not see aright
after all, nor are we right in believing that all these things are many. They
would not change if they were real, but each thing would be just what we
believed it to be; for nothing is stronger than true reality." (Based on
John Burnet's Early Greek Philosophy
(1892), with emendations by Nick Huggett.)
- But surely these arguments are based on some kind of confusion or
trick – philosophy is all about clarifying the confusions and seeing through
the tricks by careful analysis.
2. Aristotelian Change
Aristotle: 384-322 BCE
- Aristotle offers just such an analysis:
"The most appropriate way of all to begin
is to point out that things are said `to be' in many ways, and then ask in
what way they mean that all things are one. Do they mean that there is nothing
but reality, or nothing but quantity or quality?" (Physics Book I Chapter 2, trans. W.Charlton,
Clarendon Aristotle Series 1970).
- 'is' of identity ('=') vs 'is' of predication
- the 'is' of predication can be applied to distinct predicates (we could say "the tomato 'reds'" instead of "the tomato is red", as we say "the tomato grows" to mean "the tomato is growing", but is there a real danger of confusion?)
- Aristotle says change can be 'explained' in four ways:
- Material explanation: "According to one way of speaking, that from which a thing comes to be is called a `because'; e.g., in the sense that there is a statue and loving cup because there is the bronze and the silver, respectively, of which they are made." I.e., they couldn't be without the materials of the right kind
- Explanation by form:
"According to another way of speaking, the form or model is a `because'.
This is the account of what it is to be a such-and-such; e.g., there are octaves
because of the ratio 2:1." More generally, the 'form' is 'the way the thing
naturally should be' – e.g., nest should be good for laying eggs in, a spider's
web for catching flies.
- Causal Explanation: "Again, there is the primary source of the change; e.g., the man who has deliberated is the cause of his actions, the father is the cause of the child, and what changes something is the cause of what is changed."
- Explanation of Ends:
"And again, there is the end, what something is for, as health might be
what a walk is for. `Why does he walk?' We answer `To get fit'.'"
(Physics Bk II Ch, a loose translation by Nick Huggett, based on Akril's Aristotle the Philosopher)
- 2-4 often coincide: the end is the form is the cause of change – what a thing is for is what it should be is what causes it. (Phys II.7)
E.g.: "If then it is both by nature and for
an end that the swallow makes its nest and the spider its web, and plants
grow leaves to provide shade for the fruit and send their roots down (not
up) for the sake of nourishment, it is plain that this kind of cause is operative
in things which come to be and are by nature." (Phys II.8 Based on the translation by
R.P. Hardie and R.K. Gaye, with minor emendations by Daniel Kolak.)
E.g., "Locomotion is natural [to bodies] ... if upwards then it is fire or air, but if downwards water or earth." (On the Heavens I.2, a loose translation based on Leggatt 1995.) Even for material bodies, their natural motion arises because form=end=cause.
E.g., "Locomotion is natural [to bodies] ... if upwards then it is fire or air, but if downwards water or earth." (On the Heavens I.2, a loose translation based on Leggatt 1995.) Even for material bodies, their natural motion arises because form=end=cause.
- Problems: we can explain the causal powers of anything by saying
'that is what it should do'. E.g., opium causes sleepiness because producing
sleep is what nature intends it to do -- it has 'dormitive powers'.
Rene Descartes (1596-1650): He thought so he was.
- Descartes completely rejects the Aristotelian doctrine of 'forms'
as an explanation of change, and replaces it with the radical 'mechanical
philosophy'.
"... concentrate on the idea that we have
of some body, e.g. a stone, and remove from that idea everything which we
know is not essential to the nature of body... begin by removing hardness;
for if the stone melts ... it will lose hardness but will not thereby cease
to be body. We may also remove colour, for we have often seen stones so transparent
that they had no colour; we may take away weight, because although fire is
extremely light, it is nonetheless thought to be body. Finally we may take
away cold, heat, and all other properties ... which could be changed without
the stone being thought to have lost the nature of body. For then we shall
clearly notice that nothing remains in our idea of the stone except that it
is something extended in length, breadth and depth." (Principles Part II. §11 -- Miller
and Miller trans (D. Reidel Pub Co, 1983.))
All there is to being material is having (non-zero) volume -- none of the other properties are possessed by all bodies, so none can be what it is to be material. Then material objects essentially are just geometric bodies, made real. Further, their geometric properties are at bottom their only properties.
"Therefore, all the matter in the whole universe is of one and the same kind; since all matter is identified solely by the fact that it is extended. Moreover, all the properties which we clearly perceive in it are reducible to the sole fact that it is divisible and its parts movable..." (Princs II.23)
"... I know of no kind of material substance other than that which can be divided, shaped and moved in every possible way, and which Geometers call quantity and take as the object of their demonstrations. And that there is absolutely nothing to investigate about this substance except those divisions, shapes and movements." (Princs II.64)
At bottom all properties are just the result of the shapes and motions of bodies, and hence at bottom all change is simply the rearrangement of bodies – the world at base is just geometrical.
All there is to being material is having (non-zero) volume -- none of the other properties are possessed by all bodies, so none can be what it is to be material. Then material objects essentially are just geometric bodies, made real. Further, their geometric properties are at bottom their only properties.
"Therefore, all the matter in the whole universe is of one and the same kind; since all matter is identified solely by the fact that it is extended. Moreover, all the properties which we clearly perceive in it are reducible to the sole fact that it is divisible and its parts movable..." (Princs II.23)
"... I know of no kind of material substance other than that which can be divided, shaped and moved in every possible way, and which Geometers call quantity and take as the object of their demonstrations. And that there is absolutely nothing to investigate about this substance except those divisions, shapes and movements." (Princs II.64)
At bottom all properties are just the result of the shapes and motions of bodies, and hence at bottom all change is simply the rearrangement of bodies – the world at base is just geometrical.
