"柏拉图哲学的" can be translated as "Platonic" or "Plato's philosophical" in English.
"Platonic" is a commonly used adjective derived from Plato's name, referring specifically to his philosophical ideas or principles. For example, "Platonic philosophy" (柏拉图哲学) or "Platonic ideals" (柏拉图式的理念).
"Plato's philosophical" is a more descriptive phrase that explicitly attributes the philosophy to Plato. For example, "Plato's philosophical teachings" (柏拉图的哲学教义).
In most contexts, "Platonic" would be the more concise and appropriate choice.