Rationalism advocates that reason is the most important aspect to analyze anything. It says that whatever knowledge you acquire and possess, it needs to be based on reason alone. This is considered one of the most important philosophical methods, as it takes into consideration all human knowledge only based on reason and never appreciates anything outside of reason. In fact, it further adds that there cannot be a thing that can exist in the universe which cannot be brought into the realm of reason.
Rationalism is considered a great way of deducing things and a lot of famous philosophers have been rationalists. It all started with Parmenides, a Greek philosopher, who is considered the father of Rationalism. Like any other philosopher in his period, he didn’t realize that he was giving birth to a new school of thought and he simply did what he did best, that is to analyze things based on reason. After Parmenides, Zeno of Elea, his disciple, was considered the torchbearer for rationalism. Over the years, a lot of famous philosophers like Plato, Descartes, Baruch Spinoza, and Christian Wolff have been the followers of philosophical rationalism which has simply changed the course of history.
Rationalism, by definition, is a very systematic school of thought. It takes into consideration everything and tries to deduce things based solely on reason. It is like a building which is built on the foundation of reason and reason alone. The classic example of the rationalistic way of thinking is this – anything that exists in the universe is certain to have some properties. Firstly, it is not possible for the thing to come into existence and cease to exist after some point of time. In other words, it never starts to exist and stops to exist; it was always there, outside time.
The whole concept of existence is taken away from the parameter of time, as time is one parameter which reduces everything into numbers. With time, you can always say that a thing started to exist at a particular point of time and ceased to exist at another particular point of time, thus making the whole concept of existence contradictory to the basic idea of rationalism, which says that things stay eternally true. In order to make things stay eternally true, or to come to the conclusion that things stay eternally true, the concept of time should be taken away and this is the reason why rationalism, especially the one stated by Parmenides, said that things exist outside time.
Plato, though considered the most famous rationalist, changed the philosophy slightly by mixing it with realism. Plato argued that the essence of things was more important than anything for a philosopher. He also stated that essence of things stayed the same across the universe. After Plato, the concept that reason alone can give birth to substantial truths has stayed with the world and has found many takers around the world.
