The concept of humans 'evolving' into a Psyker species is an interesting concept in 40K. While chance mutation in humanity's genetic code that gives an advantage to an individual may lead to evolution of the species via offspring dominating the gene-pool, it seems that this is not the case in 40K. Psykers seem very vulnerable in 40K and most fall to chaos all too easily, yet more pop up all over the Imperium.
Psyker powers are thought to be linked to genetics, as some species have strong Psyker powers (Eldar) while others seem totally devoid of any Psyker power or even a warp image (Tau). This seems to imply that Psyker power must have some form of genetic component. However in humans it seems that chance mutations of Psykers power would never survive long enough in a population to become dominant. It could be that the genes are recessive, and that they pop up from time to time when both parents have the recessive gene. This doesn't explain why those with the recessive Psyker genes (and hence: no power) would become so popular to cause an epidemic (fall of the Golden Age).
Something else is at work here. If it was a simple gene based power humans would have found it long ago. There is evidence that such knowledge may have existed with the Navigators (and the navigator gene), these strange mutants with the third eye, is compelling. The Navigators have the power of navigation, but this power is seen as distinct from full Psyker powers; as they lack many of the proper Psyker powers and are immune to possession. It is not conclusive that all of the Navigator's powers are purely gene based. Navigators often exhibit proper Psyker powers in addition to their 'innate' abilities.
Thinking about evolution, and humanity's rise to power through technology advancement and our resultant domination of our enviroment; it seems that humans have not changed much for thousands of years. We seem pretty constant as there is no need to change as we can always overcome our enviroment with the abilities we have now. The only threat is other humans.
It's the 'other humans', and the concept of competition, I think provides the key to the Psyker conundrum. The only real evolution seen by humans is in ideas. Wars are dominated by technological superiority. They are dominated by ideas, concepts and memes (social information norms - tenants). The real evolution is in our ideas, it is the ideas that are competing with each other, mind vs mind with the body and genetics being relatively constant.
Humans in 40K may already be fully Psyker enabled: they all have the genetic code needed to draw on the warp and produce Psyker effects. The problem is that the genetic code only gives the potential for the power to exist, but that the potential has to be activated and this is where ideas come into play.
Certain ideas and concepts, memes and feelings, affect the warp image. A correct combination aligns the warp image in such a way as to activate the power. Once activated and the person is aware, they may become locked in that state of mind, or they can switch back and forth.
The activation of the power may vary from person to person depending on their own personal warp image, generated from their personality. Each person's activation sequence is different and not uniform across all humans. It is all down ideas and memes - an incredibly complex 'lock'.
This would mean that Psyker powers in 40K are indeed genetic at there core, yet it is not that simple case of a gene based power. The memes play a huge part. Therefore the Navigators may be just like all other humans with the addition of having been genetically engineered with a 'third eye'. if this adaption is combined with some meditation in a limited enviroment and isolated gene-pool (and hence isolated memes) it could make activation more predictable. The activation may be a minor part of the human Psyker power which is then boosted by the engineered adaptations. This would also explain why some Navigators develop other powers, as they are just as susceptible as other humans to spontaneous development via meme infection - that talking with other humans and picking up ideas and memes means the navigator may unlock other powers.
If this is the case: Psykers in 40K are going to be exceptionally random and with no genetic markers to distinguish them from any other human (as all humans have the same genetic 'Psyker' markers and are as such 'invisible'). A new Psyker can spontaneously pop up anywhere, the result of a mere idea, something they saw for the first time may be all that is needed to unlock the Psyker powers. A person could look at the patterns on a butterfly's wings (homage to chaos theory) and unleash an Alpha class Psyker.
New experience and ideas would increase the likelihood of unlocking powers. The Imperium may not like the idea of this happening in an uncontrolled manner. 'Travel broadens the mind', yet in 40K this may not be seen as a good thing. The reason the Golden Age gave rise to a Psyker epidemic may have nothing to do with the chaos powers, it may be down to the rapid exchange of information and the development of new ideas. The more information you have the greater the chance of unlocking a power.
Perhaps enlightenment in 40K brings about super powers, or at other times an ignorant child may stumble upon the 'key' and unlock hell (Apex Twins). Perhaps laughing hard after watching 'Happy Tree Friends' did it?
Maybe this is why many humans have developed a 'cult' of ignorance. They see accepting new ideas may lead to your downfall. That the only information your really want is the information in your own population (if stable and Psyker free). On the other hand, many may go looking for new information. It may explain why Inquisitors all seem to go nuts and gain super powers. It may have little to do with Chaos Gods and merely 'chaos'.
Hearing feedback is very important to me in developing my ideas. Much of my designs are inspired, and crafted, by chatting to fans on forums before snowballing into a full concept you'll find here. I would like to thank all those who have contributed critiques and participated in discussions over the years, and I would especially like to thank all those who commented on this specific topic. If you would like join in, you are most welcome!
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