The first key principle that every Illuminist should become familiar with is the Principle of Sufficient Reason (PSR). The PSR states that for every fact there is a reason why it is so and not otherwise. So everything must have a sufficient reason for its existence and why it is so. The PSR should be applied to any idea you come across. Test if what is being said stands up to the PSR. The video below gives a good explanation of the PSR. It may seem obvious that everything has a sufficient reason for being so, but this philosophical thinking can often be overlooked (such as in empiricist materialist science). Sometimes the given reason for the Universe’s existence is that there are random quantum fluctuations. But what is the sufficient reason for this being so and not otherwise? Does this really explain anything at all? All these problems can be looked at in far greater detail.
In short, ALL theories and ideas should pass the test of the PSR!