What is the nature of the noumenal world and how does it differ from the phenomenal world?

The noumenal world is the world as it truly is, beyond our perception and understanding. It is the realm of things-in-themselves, independent of our senses and thoughts. The phenomenal world, on the other hand, is the world as we experience it through our senses and cognition. The main difference is that the noumenal world is inaccessible to us, while the phenomenal world is the world we perceive and interact with in our daily lives.