In
philosophy, the concept of
becoming originated in eastern
ancient Greece with the philosopher
Heraclitus of Hephesus, who in the sixth century BCE, said that nothing in this world is constant except change and becoming. His theory stands in direct contrast to
Parmenides, another Greek philosopher, but from the italic
Magna Grecia, who believed that the
ontic changes or "becoming" we perceive with our senses is deceptive, and that there is a pure perfect and eternal being behind nature, which is the ultimate truth. In philosophy, the word "becoming" concerns a specific
ontological concept which should not be confused with
process philosophy as a whole or with the related study of
process theology.