Why did William of Ockham deny that universals exist apart from individual things?

William of Ockham denied that universals exist apart from individual things because he was a nominalist, maintaining that reality consists entirely of particulars.12

His rejection of universals is deeply connected to his famous principle of parsimony, known as Occam’s razor, which states that "plurality should not be posited without necessity". Ockham argued that the existence of universals—whether as independent Platonic forms or as constituents within things—was unnecessary to explain the world.312

Instead, he contended that general terms are merely words or symbols used to denote groups of similar particulars. He believed that the application of these general terms is sufficiently explained by the inherent similarities among individual things, rather than by the existence of some separate, abstract entity. By removing these metaphysical "entities," Ockham sought a simpler, more direct explanation of reality that focused solely on the individual objects observed in the nonlinguistic world.243