Why exactly do negatives entities inevitably need to switch polarities?

[Aion]

I wouldn't say so much that they avoid the truth so much as test the limits of it as far as they can. Negatives at that level are well aware of the paradox but some will spend quite a long time trying to find a way to circumvent it.

Not sure if negative polarity avoids the truth. For me negative polarity is the original instinctual polarity, by only looking at the evolution and enabling of energy centers. In second density only negative polarity is possible and is subconscious. Some entities which are strongly driven by survival instincts will have these tendencies even after all centers are enabled. It's not like they know the truth but pretend they don't. It is what their free will tell them is true. They only abandon their way when the spiritual evolution they desire becomes impossible while individuality is maintained.

I guess that would be up for anyone's opinion. According to Ra the early stages of evolution were purely positive and the negative polarity didn't occur until 'later on' in the chain. I can't say I agree with your assessment of second density but maybe we understand it in different ways.

I think what you describe regarding survival and instincts being negative doesn't really ring true to me. According to the system of Ra polarity doesn't even 'start' until the third density. Not that I follow the 'system' but these are debatable points.