Only fragments of Heraclitus survive, quoted by later writers. The ancients nicknamed him "the Obscure" — and his best-known line is actually Plato's summary of him.
3 real · 0 not theirs
Really theirs
3 quotes traced to Heraclitus's own work or a reliable witness.
Sourced
Character is destiny.
Source: Fragment B119
Sourced
The way up and the way down are one and the same.
Source: Fragment B60
Attributed
You cannot step twice into the same river.
Plato's paraphrase; Heraclitus' own fragment (B12) speaks of different waters flowing over those who step into the same rivers.