Philosophy of Religion

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Plato's justification for the existence of the Soul

Plato clearly believed that each person has a soul which lives on after the body dies; he also wanted to show that (in his view) this belief is reasonable and can be justified through logical argument. His dialogue Phaedo is mainly concerned with these arguments; Cebes, the person who is in dialogue with Socrates, suggests that perhaps the soul just disappears, like smoke, into nothingness when the body dies, and he asks for some kind of persuasive argument to justify Socrates’ belief in the immortality of the soul.

The Argument from the Cycle of Opposites

Plato’s first argument relies on the idea that every quality comes into being from its own opposite. It depends on the existence of its opposite, or it would not exist at all. He argues that big things would not be bigger or small things smaller without their opposites; they depend on their opposites for their existence. In the same way, people who are awake are just people who were asleep but then woke up, while people who are asleep are just people who were once awake. The idea very much influenced Augustine in his understanding of evil, as a quality that is the absence of goodness rather than a real power in its own right.

Are not all things which have opposites generated out of their opposites? I mean such things as good and evil, just and unjust.

Plato argued that it followed that death must come from life, and life from death. That is, people who are dead are just people who were in the past alive but then experience the change we call dying, and people who are alive are just people who were among the dead but then experienced the change we call being born. Plato’s thought suggests an endless chain of birth, death and rebirth.

The Argument from knowledge

As we have already seen, Plato thought that the most important kinds of human knowledge are really remembering, ‘leading out’ things which we already knew. For example, according to Plato, we have our knowledge of equality even though we have never seen any two things that are perfectly equal, because there will always be some minute difference; and yet we know what true equality (or the Form of Equality) must be.

Plato thought that the same was true of many other abstract concepts: even though we only ever experience imperfect examples, we have genuine knowledge of truth, goodness, and beauty, just as we have true knowledge of equality and circularity. Plato distinguished this kind of knowledge from the sort of inferior, temporary, unreliable ‘knowledge’ that we might gain through the senses but which is merely opinion. Plato believed that this knowledge of the Forms must be innate, and must have been gained by our souls before we were born. When we come to understand something that is the object of true knowledge, such as the square root of 81, which is not available to the senses but is true for all time, we have a sense of recognition. For Plato, this was evidence that the soul pre-existed the body.

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