Which philosopher believed in the dual existence of a perfect world and an imperfect world through his theory?

Plato is the philosopher known for his theory of dual existence, which posits that there are two realms: the world of forms (or ideas) and the world of appearances. In this philosophical framework, the world of forms represents a perfect, unchanging reality that encompasses ideals such as beauty, justice, and equality. In contrast, the world of appearances is the flawed, material world that we experience with our senses, where objects are mere shadows or imitations of the perfect forms.

This division highlights Plato's belief that knowledge can only be attained through reasoning and intellectual understanding of these ideal forms rather than through sensory experience, which can be misleading. His famous allegory of the cave exemplifies this concept, illustrating how most people are confined to a limited perception of reality, while true understanding comes from recognizing the higher, perfect truths that lie beyond immediate experience. This dualistic perspective laid the groundwork for later philosophical discussions regarding reality and perception.