Heraclitus

(c.535 BC - 475 BC) was a Greek philosopher, known for his doctrine of change being central to the universe, and for establishing the term Logos (λόγος) in Western philosophy as meaning both the source and fundamental order of the Cosmos.

Everything flows, nothing stands still.

Nothing endures but change.

Good character is not formed in a week or a month. It is created little by little, day by day. Protracted and patient effort is needed to develop good character.

You could not step twice into the same river; for other waters are ever flowing on to you.

Πάντα ῥεῖ καὶ οὐδὲν μένει
- Everything flows, nothing stands still.
- Quoted by Plato in Cratylus, and by Diogenes Laërtius in Lives of the Philosophers Book IX, section 8
- Variant translations:
  Everything flows and nothing stays.
  Everything flows and nothing abides.
  Everything gives way and nothing stays fixed.
  Everything flows; nothing remains.
  All is flux, nothing is stationary.
  All is flux, nothing stays still.
  All flows, nothing stays.

Nothing endures but change.
- From Lives of the Philosophers by Diogenes Laertius
- Variant translations:
  There is nothing permanent except change.
  Nothing is permanent except change.
  The only constant is change.
  Change is the only constant.
  Change alone is unchanging.

Eternity is a child playing, playing checkers; the kingdom belongs to a child.
- Quoted in Hippolytus, as translated in Reality‎ (1994), by Carl Avren Levenson and Jonathan Westphal, p. 10
- Variant translations:
- History is a child building a sand-castle by the sea, and that child is the whole majesty of man’s power in the world.
  - As quoted in Contemporary Literature in Translation‎ (1976), p. 21
- A lifetime is a child playing, playing checkers; the kingdom belongs to a child.
  - As quoted in The Beginning of All Wisdom : Timeless Advice from the Ancient Greeks‎ (2003) by Steven Stavropoulos, p. 95
- Time is a game played beautifully by children.
  - As quoted in Fragments (2001) translated by Brooks Haxton
- Lifetime is a child at play, moving pieces in a game. Kingship belongs to the child.
  - As quoted in The Art and Thought of Heraclitus (1979) translated by Charles H. Kahn