Home | Texts by category | | Quick Search:   
Works by Aristotle
Pages of Physics

Previous | Next


Part 1
When the objects of an inquiry, in any department, have principles,
conditions, or elements, it is through acquaintance with these that
knowledge, that is to say scientific knowledge, is attained. For we do
not think that we know a thing until we are acquainted with its
primary conditions or first principles, and have carried our analysis
as far as its simplest elements. Plainly therefore in the science of
Nature, as in other branches of study, our first task will be to try
to determine what relates to its principles.
The natural way of doing this is to start from the things which are
more knowable and obvious to us and proceed towards those which are
clearer and more knowable by nature; for the same things are not
'knowable relatively to us' and 'knowable' without qualification. So
in the present inquiry we must follow this method and advance from
what is more obscure by nature, but clearer to us, towards what is
more clear and more knowable by nature.
Now what is to us plain and obvious at first is rather confused
masses, the elements and principles of which become known to us later
by analysis. Thus we must advance from generalities to particulars;
for it is a whole that is best known to sense-perception, and a
generality is a kind of whole, comprehending many things within it,
like parts. Much the same thing happens in the relation of the name to
the formula. A name, e.g. 'round', means vaguely a sort of whole: its
definition analyses this into its particular senses. Similarly a child
begins by calling all men 'father', and all women 'mother', but later
on distinguishes each of them.
Part 2
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.
A similar inquiry is made by those who inquire into the number of
existents: for they inquire whether the ultimate constituents of
existing things are one or many, and if many, whether a finite or an
infinite plurality. So they too are inquiring whether the principle or
element is one or many.
Now to investigate whether Being is one and motionless is not a
contribution to the science of Nature. For just as the geometer has
nothing more to say to one who denies the principles of his
science-this being a question for a different science or for or common
to all-so a man investigating principles cannot argue with one who
denies their existence. For if Being is just one, and one in the way
mentioned, there is a principle no longer, since a principle must be
the principle of some thing or things.
To inquire therefore whether Being is one in this sense would be like
arguing against any other position maintained for the sake of argument
(such as the Heraclitean thesis, or such a thesis as that Being is one
man) or like refuting a merely contentious argument-a description
which applies to the arguments both of Melissus and of Parmenides:
their premisses are false and their conclusions do not follow. Or
rather the argument of Melissus is gross and palpable and offers no
difficulty at all: accept one ridiculous proposition and the rest
follows-a simple enough proceeding.
We physicists, on the other hand, must take for granted that the
things that exist by nature are, either all or some of them, in motion
which is indeed made plain by induction. Moreover, no man of science
is bound to solve every kind of difficulty that may be raised, but

Previous | Next
Site Search