Summary:
Plato's theory which postulates that all knowledge that has ever been known and will ever be known is already preexistent in your memory; thus time is an illusion, merely the unfolding process of remembering everything. Such a recollection is known as anamnesia. This theory would explain both deja vu and synchronicity. It might also imply that we are headed for the Omega Point.
Details:
In Plato’s Phaedo, Socrates is on his deathbed and chooses to address the question of the fundamental nature of reality. He attempts to prove to both himself and to those around him that the human soul exists beyond the physical world as an undying entity which both precedes and outlives the human body. One of the key elements to Socrates’ argument for the immortality of the human soul is his Recollection argument which points to evidence that human beings know more than they could have learned from their existence on earth. In essence, time and learning are illusions because all knowledge and all events are already contained in memory. Reality is merely the unfolding process of remembering. This is analogous to watching a movie you saw a long, long time ago; you've seen everything before but none of the content is familiar. (Except when you get deja vu).
The first piece of evidence presented on this theory's behalf is the tale of Socrates and Meno’s slave. Perhaps one of the greatest mathematical accomplishments of ancient Greece was the proof of Pythagoras’ theorem. In the Meno, Socrates presents a slave, having no mathematical background whatsoever, with a series of simple geometrical diagrams and questions, asking him to make basic conclusions after each. In essence, this slave, with no mathematical training, is able to prove the very theorem which had puzzled the great minds of their day. Consequently, according to Socrates, as the slave could not have acquired the knowledge of how to prove this theorem during his lifetime on earth, the only way that he could have done this proof is to have had the knowledge of it available to him before he was born. Socrates proposes that as he is not learning something new, he is merely recollecting knowledge that he already had from a previous existence.
Socrates furthers his argument by introducing his theory of Forms. What he proposes is that, underlying the physical and concrete elements of our world exist abstract entities to which we have no access through our senses, namely, the Forms. They consist of such things as Beauty, Justice, Circularity, Equality, and the concept of Two. While these entities are understood by all of man, man could not have become acquainted with them in the manner that he becomes acquainted with normal physical entities. We can know what a circle is because we can see a circle and even hold one, but we could not have come to learn of Circularity in this manner. A circle in Mexico and a circle on mars both have Circularity, and perhaps a sentence or a musical phrase being repeated over and over again has a sense of Circularity; it is an abstract essence that many things have in common, but it has no definite place or absolute distinct feature. Since we have no access to the Forms through our senses we have no way of encountering or learning about them in this manner. Hence, Socrates poses the question: How did we come to be acquainted with these Forms if it was not through our senses? His answer is that we come to know and understand the Forms in the same manner that the slave proves Pythagoras’ theorem, by recollecting knowledge we had of them before this lifetime.
John Lerch, 1998