Why did Plato regard the Forms as more real than changing physical things?

Plato regarded the Forms as more real than physical objects because he viewed the sensible world as inherently unstable and imperfect, whereas the Forms are eternal, unchanging, and ontologically basic.123

In Plato’s philosophy, physical things are perceived by the senses and are constantly changing, "rolling around between being and not-being," meaning they never fully embody the qualities they possess. For example, no physical object is perfectly beautiful or perfectly equal; they are merely imperfect copies that participate in the higher, absolute reality of the Forms.124

Because sensible particulars are constituted by and explained through these fundamental entities, they are not considered fully real in the same sense as the Forms. Plato argued that to truly understand concepts like beauty, justice, or equality, one must look beyond the flawed, shifting realm of the senses to the eternal world of the Forms, which serves as the foundation for all knowledge and existence. In his myth of the cave, he illustrated this by comparing ordinary sensory experience to watching shadows on a wall, while the Forms represent the true, illuminated reality outside.51243