Parmenides (also Parmenides of Elea) (, early 5th century BC) was an ancient Greek philosopher born in Elea, Italy and was the founder of the Eleatic school of philosophy. His only known work is a poem, but only bits and pieces have survived. In it, he describes two views of reality. These thoughts strongly influenced Plato, and later, the whole of western philosophy. His philosophy was based on materialistic monism. Materialistic monism is the belief that everything in the universe is made of a single substance. Parmenides' biggest argument was that change does not exist. Parmenides' explanation is that we think we see change, but our senses are not reliable, and they create the illusion of change.