Why did Parmenides argue that change and motion are illusions?

Parmenides argued that change and motion are illusions because he believed that the only true reality is a single, eternal, and unchanging entity he called Being.31

His reasoning was rooted in a strict rationalist approach that prioritized logical consistency over sensory perception. Parmenides contended that:52

• The Nature of Being: True reality, or eōn, is pure, immutable, and indestructible. Because it is a complete and "well-rounded" whole, it cannot have a beginning or an end, nor can it change, as any change would imply a transition from or to "Not-Being," which he argued is logically impossible.31
• Rejection of Multiplicity: He maintained that the world of daily experience—characterized by birth, death, growth, and movement—is merely a "Way of Opinion" or appearance. Since these phenomena involve change, they contradict the static, eternal nature of true Being.415
• Logic over Senses: While human senses suggest that objects move and change, Parmenides insisted that reason must be the ultimate arbiter of truth. He concluded that because change is logically self-contradictory, it cannot be real.51

Would you like to learn more about how his student, Zeno of Elea, used paradoxes to further defend this view?