Fl. 500 B.C. in Ephesus, north of Miletus in Asia Minor. He was known in antiquity as
“the obscure.” And even today, it is very difficult to be certain what Heraclitus was
talking about. As Barnes says (
, p. 57):
“Heraclitus attracts exegetes as an empty jampot wasps; and each new wasp discerns traces of his own
The reason for this is Heraclitus’s dark and aphoristic style. He loved to appear to
contradict himself. Some of his doctrines sound incoherent and self-contradictory even if
he did not perhaps intend them that way.
One thing seems certain: Heraclitus had an extremely negative reaction to Milesian
thought. For the Milesians, what is real is fixed and permanent;
somehow had to
be explained away. They understood changes as alterations of some basic, underlying,
material stuff which is, in its own nature, unchanging. Heraclitus reversed this: change is
what is real. Permanence is only apparent.
Heraclitus had a very strong influence on Plato. Plato interpreted Heraclitus to have
believed that the material world undergoes constant change. He also thought Heraclitus
was approximately correct in so describing the material world. Plato believed that such a
world would be unknowable, and was thus driven to the conclusion that the material
world was, in some sense, unreal, and that the real, knowable, world was immaterial.
The unity of opposites
A number of fragments suggest that Heraclitus thought that opposites are really
(= B61, B60, B88, B67, B62)
What does this mean? Does Heraclitus think that hot = cold, that mortality = immortality,
etc.? Does he think, in general, that each property
that has an opposite
its opposite? Is the unity of opposites thesis best understood (in logical symbols) as:
Φ = Φ ′
This is not likely. The fragments suggest, rather, that he thinks that
opposites may be
in the same thing, or
That is, that one and the same thing may be
both hot and cold, pure and polluted, etc.
But what claim is Heraclitus making about the coinstantiation of opposites? Here are a
couple of possibilities:
Some object instantiates at least one pair of contrary properties.
Every object instantiates every pair of contrary properties.
Of these, (a) seems insufficiently general to be of much interest, and (b) seems too
strong to have any plausibility.
Barnes suggests that the unity thesis can be represented as a conjunction of the following
Every object instantiates at least one pair of contrary properties.