The prefix 'theory of' is inferred in random being used as an abstract noun, without confusion, because it has no other alternative meaning in the relevent context. Evolution, as opposed theory of evolution, is an example.
This doesn't make much sense. Are you saying that there exists a "Theory Of Random"?
The correct noun is "randomness". The word "random" is an adjective. For the sake of clarity you would better serve your own ends by using the word in the usual manner.