born in Clazomenae in Ionia Anaxagoras spent most of his life in Athens. He
returned to Ionia about 450 after he had been condemned for alleged impiety by
the political opponents of his famous pupil Pericles. He was influenced by both the Milesians and the
Eleatics; and his philosophy may be regarded as an attempt to reconcile these
two schools of thought.
COSMOLOGY/ PHILOSOPHY OF NATURE
 Anaxagoras rejected the idea of a coming into existence
out of nothing and the cessation or
destruction of Being. Change, he said,
is real, but there is no change of quality [a]. But he also said that individual things
could not have come into existence from other things: "How could hair come into existence out of
non-hair, or flesh out of non-flesh?" [fr. 10]. He supposed there to have been an original mixture (constituting unitary Being) of an
infinite number of eternal elemental things or 'stuffs' (chremata). It is as a result of the
rearrangements of things through combination and separation that change occurs [b]. These 'stuffs' included opposites [c] such as hot and
cold, moist and dry; earth, air and aither (that is, upper air); and
innumerable 'seeds' (spermata)
different from each other wood, bone,
gold, blood, and so on [see fr. 4]. (Aristotle later called some or all of these stuffs 'homoiomere', which means 'similar parts'
[see Physics A4, 187a23; On the Heavens Γ3, 302a281].) Anaxagoras said that air and aither were the greatest in so far as they
were present in the greatest quantities and held the others in subjection [fr.
1]. The others would not have been distinguishable in the original
mixture because of their smallness [fr. 4]. All stuffs are
infinitely divisible [fr. 3] [d]. He argued
further that "all things
are in everything"; "everything contains a portion of everything" [fr.
6] [e]. Anaxagoras
seems to have meant that each different stuff contains portions of all the
other stuffs in small quantities, each of which in turn contains portions of
the others. Thus a piece of wood, for
example, contains portions of gold, ash, bone, etc., although the wood stuff
predominates in the mixture. And he
rejected the idea that these stuffs can exist separately from the homogeneous
mixture which constitutes a thing:
And since too there are equal portions of great and
small in quantity, for this reason also everything is in everything; nor can they exist separately, but everything
shares a portion of everything. Since
the least cannot be, things cannot be separated nor come to be by themselves,
but as in the beginning, so also now everything is together. [Fr. 6]
 As for the world as a whole, Anaxagoras said that it comes into being as a result of
a rotation of the boundless (apeiron) [a]. The primary controlling
substance of the cosmos is termed nous, that is, 'mind' or
intelligence [b]. It is through its agency that opposites
separate out from the boundless into individual things, nous itself being pure and unmixed [fr. 13]. Individual minds or souls are
supposed to be made up of this same substance [c],
though what Anaxagoras believed the relationship between these minds and nous to be is not made clear. Nous seems to be a material rather than a spiritual principle, "albeit the thinnest
 While allowing for the
possibility of error in our perception of the world, Anaxagoras does not accept that our experience is
totally illusory. We can gain
some knowledge of it through the senses: "Appearances are a glimpse of the obscure" [fr. 21a]. His theory is that sensation occurs when unlikes act on unlikes [a]. Thus we can experience a warm object
when our hand is relatively cold.
Anaxagoras's idea of 'seeds' is of course original and
interesting. It has been objected that
his theory is not coherent because it involves an infinite regress: all stuffs are made of other stuffs each of
which contains all the others, and so on. But this regress can probably be avoided if his idea of predominance is
emphasized. While the gold, ash, and so
on which make up the wood are themselves made up of other stuffs, the gold
stuff is called gold, and the ash stuff is called ash, because it contains more
of that than the other stuffs. Nevertheless this would seem to commit Anaxagoras to making a
distinction between the seed gold and a stuff gold; and it is debatable whether
this can be reconciled with his idea of infinite divisibility.
also problems with his notion of the nous. Plato and Aristotle criticized him for using
the concept as a stop-gap and perhaps for not being sufficiently
radical. Quite apart from the question
whether it is spiritual or 'thinly' material (it is probable that even in
Anaxagoras's day no such clear distinction had been made), there is the problem
of how the nous can remain pure and
unmixed if it in some sense permeates the individual mind.
Kirk, J. E. Raven, & M. Schofield, The Presocratic Philosophers, ch.
R. D. McKirahan, Philosophy Before Socrates, ch. 13.
M. Schofield, An Essay on Anaxagoras.
See also essays by G. Vlastos (in Mourelatos, and Furley and Allen); and
by C. Strang (in Furley and Allen).
not totally illusory; perception
through unlikes on unlikes