Plato’s metaphysics was based on the ideas, which were taken from within and applied to the outer world, while Aristotle used the ideas from the surrounding world to apply them within. Thus, Plato believed in a dualistic reality (there are mental and physical things), and Aristotle claimed that only an imminent reality exists. Unlike Plato, Aristotle believed that forms could not exist separately but only in an object itself. This explains why these philosophers differently determine what is true and false. Aristotle claims that something is true if he has seen it and knows it. Plato, on the contrary, uses intuition and common sense to prove something true or false.
Rationalism argues that a person is born already with knowledge, i.e. knowledge is inherent, and learning stems from intuition. Empiricists, on the contrary, claim that one can know something exclusively on the basis of direct sense experience. Following Rationalists, who are concerned with absolute universal truths, one can assert that the mind is the single source of knowledge. Empiricists reject this principle and make use of the postulate that a person is born with the mind as blank as a slate, i.e. without any knowledge or experience. Therefore, only human sensual experiences can serve as a background for knowledge.
Plato’s belief in reincarnation may affect his understanding the nature of human happiness in the following way. He may believe that happiness is a fluid notion, just like his Forms, which implies that a person can achieve happiness not in earthly but next life, or has already achieved it in previous lives. Aristotle’s materialistic view on reality may make him believe that happiness is the ultimate goal of human earthly existence, i.e. people should achieve happiness till the end of their life. Aristotle’s rejection of afterlife does not make happiness a permanent state (as in Plato’s case) but defines it within the frames of earthly life.
Plato’s low opinion of democracy seems rather reasonable. The point is that poor citizens prevail in a state, and they dislike being deceived by rich rulers. Falsely, the poor believe that they know what they need, but these needs are illusory - lust after power and sensual pleasures. The masses, which are uneducated and ignorant about the essence of the soul, cannot realize what true needs imply. According to Plato, the poor, unless educated into arts and philosophy, are incapable of distinguishing true needs from illusory ones and electing a good ruler. Only a philosopher as a ruler can satisfy citizens’ true needs, which lead to wisdom and spiritual growth.
It seems to me that Plato implicitly rejected slavery in any form since it contradicted his notion of justice. Plato’s just society consists of three classes, with each class performing its role. However, in a just city, every person should do exclusively what he or she is good at and not interfere in other people’s business. According to Plato, only this condition can contribute to the perfect pursuance of one’s duties. If there were slaves in Plato’s just society, they would interfere in their masters’ business, which would prevent the latter from appropriate pursuing their duties on their own.
God’s existence is so important for Descartes’ philosophy because it convinces him that other distinct things also exist. For Descartes, God cannot be a deceiver because He is a perfectly good and impeccable being. Descartes’ faculty to judge can come only from God, and if he uses it properly, he cannot mistake. Since God does not deceive, Descartes stresses that if he perceives something as a clear and distinct truth, it will be so under any conditions, even if he forgets the arguments that led him to that inference. Besides, God is also the source of human free will which is infinite since its scope is wider than the scope of human finite intellect.
Descartes continues Plato’s tradition of rational perception of the world
Rationalists are concerned with absolute universal truths and assert that the mind is the single source of knowledge. Likewise, Plato is concerned with the eternal and perfect Forms that shape reality. Both Plato and Descartes believe that knowledge exists in the human mind before a person is born. For Plato, perfection and true knowledge “is hidden” in the Forms, which, in turn, exist separately from material objects. This implies that all a person should do is to reach out to Forms. Like Descartes, Plato argues that the outside world can be understood by means of reasoning.
The phrase “epistemological detour” implies one of the means of discovering a metaphysical truth through an indirect epistemological investigation into what can be known about some phenomenon rather than a direct inquiry about its essence. The epistemological detour emphasizes the role of the mind and primary knowledge in cognition. This can be explained by the fact that rationalists believe in the infinite abilities of the human mind and that the world can be perceived rationally. Taking into consideration the epistemological detour, it becomes clear why rationalists reject the supernatural since the latter lacks reasonable evidence and cannot be convincing enough.