Cressie asked:

How could Thales of Miletus consider that fire came from water — as his theory says that everything
came from water?

============

Remember that the ancient Greeks, and indeed everyone up to the last century or so, had no real
idea as to what "fire" and "water" referred to. We know, now, that fire is, roughly speaking, a dynamic
state of rapid oxidation accompanied by light and heat, and water is a particular compound of
hydrogen and oxygen. Fine. But the Greeks had no idea of any of this, nor even of the idea, for the
most part, that substances were comprised of combinations of other substances down to the level we
now know this to be true. They did realize that mixtures were combinations, but only down to a certain
point. So fire was an actual substance for Thales, and so was water, not a compound, not a dynamic
process. Fire corresponded better, perhaps, if you want to really stretch the metaphor, to what we
term "energy" now. Given that, he could say that plants, for example, were in part comprised of both
fire and water.

Steven Ravett Brown

Is uncertain whether Thales believed that everything iswater (the claim attributed to him by Aristotle)
or only that everything comes fromwater, which is what you are saying. However, on either
interpretation, there seems to be a problem with explaining fire.

Let's take the second alternative first, because it is easier. Why is it a problem that fire 'comes from'
water? Because water is wet and fire is dry? or rain feels cold and fire feels hot? Thales could have
pointed out that if the sheer fact of change is perceived as a problem, then anyperceived change in
anything is a problem, even in a tiny degree. (That was before the Presocratic philosopher
Parmenides who came up with an astounding argument that change or differentiation of any kind are
logically impossible. It would take me a lot longer to answer thatquestion.)

More difficult is the claim that fire really iswater. What could that mean? If that is what Thales
thought, then he meant it in the same sense that ice and steam really arewater. One and the same
substance or stuff can have different perceptible qualities at different times. However, if you think
about it, there is no difficulty in principle with including fire as one of the forms of water, that doesn't
apply to steam or ice. Think of a property of fire (e.g. incandescence) that it seems hard to imagine
being a property of water. Well, it is equally hard (Thales would have said) to imagine that solidity is a
property of water. The only difference between the two cases is that we have seen water solidify
(freeze), but never seen water turn into fire.

Geoffrey Klempner

The first thing you need to understand, Cressie, is that Thales did NOT have a "theory" at all. To
maintain this is to misunderstand completely what drove him and his successors to investigate
Nature. Thales was looking for a "principle", a word which originally meant (and still does) "something
that comes first before everything else". In the world of Thales that "first" thing was (as it is in most
religions) a divinity: a creator God or some spirit or demon. And so Thales, like the other people
around him who had begun questioning the standard religious tales in the context of whether religious
stories are actually believable, decided they are not. But there was no science around in those days,
so Thales put forth a proposition - a discussion point as we might call it today. Let us discuss, he
might have said, if water, which seems to be everywhere around us, everywhere in us, everywhere in
things (even those that seem at first glance to be totally dry) might be the "first substance" on which
everything depends.

So, forget the term "theory". This is a modern short-hand for something much more fundamental, in
fact something philosophical. And from this you should take away with you the important difference
between having a theory and philosophising: namely, that theories are ideas about something
"believed to be true for the time being", whereas philosophies are efforts to establish truths which
may hold forever. That difference is not always adhered to, even by philosophers. But if you need an
example: a THEORY is the belief that "space" (i.e. the universe) is a container in which objects are
placed, while a PHILOSOPHY is the notion that, in order to hold such a belief, one should furnish a
"Sufficient Reason" for it. As you can see, these are worlds apart; and so (as I said) in Thales the
THEORY and PRINCIPLE of water as the basic substance of all things are also worlds apart.

Jürgen Lawrenz

Sydney