Shintoism

Shintoism is the most popular religion in Japan, along with Buddhism. It is focused on the worship of invisible beings and powers called Kami. They are not gods but spirits that are present in our world. Shintoism states that if Kami are treated well, then they will come into our lives to bring goodness.
http://www.bbc.co.uk/religion/religions/shinto/ataglance/glance.shtml

I believe Shintoism is more closely related to Epistemological solipsism than it is to rationalism or empiricism. Rationalism is concerned with using information that is intellectually deduced, but with this religion, this isn't really the case. Since Shintoism is a belief system that was created with the shared ideas of different Japanese people, the religion was not "deduced" or rationalised, but just conjured within the minds of people. Empiricism is more focused on sensory details, such as having to be able to see or feel something to believe that it exists. This goes even further from Shintoism than Rationalism since with this religion is only about your mindset. People can only visualize the various Kami, but cannot actually see them. So, Epistemological solipsism is the only choice that remains. This concept is about the realm outside of our own minds, and how we know whether this is true or not. The conclusion is that we can't. In the same way, no one can know whether these Kami actually exist or not. Those who do believe in them will follow Shintoism, and those who don't believe in them will not follow this religion.
http://en.wikipedia.org/wiki/Epistemological_solipsism

A strength of Epistemological solipsism is that it cannot be disproved when associated with Shintoism. No one has solid proof of the existence of Kami, nor does anyone have proof of their non-existence. So, any arguments made on either side can only be based on your own beliefs and your own mind, which is exactly what Epistemological solipsism is about.

This way of thinking and reasoning interests me a lot since it is so different from rationalism and empiricism, which are the two main ones that I'd known about. They are about the external environment, since they offer two different ways to explain your surroundings (deduction vs. sensory proof). However, Epistemological solipsism is about the internal environment, or more accurately, your own mind. There is no way to know that anything outside of this is true or exists at all, and I agree with this. I don't know if it is valid, nor will I ever know, which may be why I like this idea so much.