Step 1: Theory of Becoming Explained.
The theory of Becoming is primarily associated with the pre-Socratic philosopher Heraclitus. His famous dictum, "everything flows" (Panta Rhei), signifies that the universe is in perpetual flux and that reality is defined by this continuous movement.
Step 2: Evaluating the Candidates.
- 1. Plato: Plato's theory of forms posits that the material world is a mere shadow of an immutable, perfect realm of forms, contrasting with the concept of Becoming.- 2. Protagoras: While Protagoras declared "man is the measure of all things," he did not formulate the theory of Becoming.- 3. Heraclitus: Correct. Heraclitus is credited with the theory of Becoming, emphasizing constant change.- 4. Parmenides: Parmenides advocated for the opposite of Heraclitus, arguing that change is illusory and that "being" is static.
Step 3: Determination. The correct attribution is 3. Heraclitus.
Final Answer: \[ \boxed{\text{The correct answer is 3. Heraclitus.}} \]