In modern times, the everyday usage of the term “materialism” has a very different meaning compared to how ancient Greek philosophers like Plato, Socrates and Aristotle would have used it. When contemporary people speak of a materialistic person, they are most likely thinking of someone who places very high value on money and material possessions, and is perhaps also selfish, greedy and narcissistic. They care more about things than they do about other people, or about ethics, relationships and the larger society. A materialist like this is the product of a modern consumer society, which of course was very different from the ancient world.
By current standards, there simply was not all that much to consume back then, although there were certainly very wealthy people who lived in luxury and did not have to work, just as there are now. Greek philosophers were well-aware that such people existed in their time, including those who cared only about physical pleasure, money, and gluttony, and they had an extremely low opinion of them. People like those were the exact opposite of philosophers in that they cared nothing about truth, ideas, morality or politics but only their own comfort and well-being. Were they alive today they very likely would have thought that modern society produces far too many people like these, and that they were simply taking up space without ever bothering to use their minds for any significant purpose.
Beyond this commonplace definition of materialism, though, ancient Greek philosophers would also have used this term as the opposite of idealism. Plato in particular has always been described as a philosophical idealist, although in reality Aristotle shared many of his views as well. One way to think of Platonism is that it really was intended to be a kind of religion, and indeed the later Christian philosophers like Augustine realized their faith had a great deal in common with Greek philosophy. A philosophical materialist essentially believes that the physical world as perceived by the senses is the “real world” and that nothing exists except matter. This world can be explained scientifically, although the concept of “science” in the modern sense did not exist yet in the ancient world (they would have called it natural philosophy), but it really meant that no other unseen or invisible worlds existed beyond that which could be seen, heard and tasted.
For Plato, on the other hand, this material world was merely transitory and temporary, and the goal of philosophy was to discover the ideal world beyond that perceived by the senses. Plato believed this was an external, perfect and unchanging world, created by God and expressed in Ideal Forms. There was a higher truth and a higher morality that existed forever, and the physical world was simply a pale copy and reflection of it. He also thought that even though the physical body dies, the soul is eternal and therefore far more important than the world of mere appearances.
Modern materialistic and scientific philosophers strongly rejected this type of idealism, particularly because it just seemed too spiritual, metaphysical or religious. They would deny the existence of the soul, for example, or the “ghost in the machine” as Gilbert Ryle called it, and assert that the mind is synonymous with the brain. Similarly, they would dismiss the idea of an eternal spiritual world, including heaven and hell, as scientifically unproven and therefore meaningless. For those who are more religiously inclined, however, the philosophical idealism that affirms the existence of the eternal, the spiritual, God and innate ideas is far more compatible with their views.
