Parmenides and Zeno were influential Pre-Socratic philosophers who had distinctive views on the nature of reality. 

Parmenides proposed a monistic perspective, asserting that only "being" or existence is real, while non-being is illusory. He argued that change, multiplicity, and the sensory world were deceptive and unreliable. Parmenides believed in the power of reason and logical thinking to uncover truth. 

On the other hand, Zeno of Elea is renowned for his paradoxes, which aimed to challenge the concept of motion and change. His paradoxes explored the idea that motion might be an illusion or that infinity could be problematic. Zeno's paradoxes were also intended to defend Parmenides' ideas, showing the contradictions inherent in the belief of a changing, sensory world, while advocating for Parmenides' concept of a single, unchanging reality. Moreover, Zeno's contributions significantly impacted the philosophy of mathematics, especially regarding the concept of infinity.