Revised Psychic Power Rules

[InquisitorHeidfeld]

A recessive trait could easily only show in one in a million people, even is one in every thousand carries it.

A recessive trait isn't the same as an emergent one though (and even so I can't find a congential defect with anything close to a one in a million risk).
To say that Humanity is an emergent psychic race based on a one in a million incidence is like saying that we're an emergent amphibious species due to the incidence of webbed toes (incidence of webbed digits is significantly higher than one in a million) or that the entire of humanity has ginger hair and that anyone who isn't is just a statistical anomaly (incidence of red or ginger hair is also greater than one in a million, and that's globally).

Recent estimates say that there would be about ten billion planets in the galaxy of the right size to support life, about half a billion of those would be in the habitable zone. Owning just a million of these of course is quite an accomplishment but leaves space for plenty of others. I would guess that most planets won't even have been discovered yet by the Imperium, there are just so many.

The Imperium covers 90% of the galaxy, following lines of stellar density. It doesn't control every planet within its territory of course but it's constantly trying to expand so the easy ones (the ones requiring little or no terraforming) are going to be snapped up pretty quickly.
As I said above, just one tenth Imperial control (9 billion stars), one tenth planets (900 million planets) and one tenth populations (90 million planetary populations) with a one million to one incidence of psychic ability still leads to nine hundred billion psykers (assuming an average population of 10 billion/planet).

You can't circumvent Thermodynamics. But, Hive Worlds are not a closed system.

Bang to rights there... Apologies, I misspoke.

Energy intercepted is wildly different to usable energy.

Of course - the numbers used provided an extreme limit rather than an expectation of future population growth 

there's inherent inefficiencies, you'd have to remove the oceans (which would mess up the climate so much that we, and all food sources, would be dead)

I can imagine early, heavily terraformed Agriworlds "paving over" the oceans so that planting can occur above while the water becomes available for irrigation systems without those annoying losses to evaporation and indeed, if I remember correctly the maps/diagrams of Necromuda published as part of the Confrontation background had effectively done the same (though they'd done it with sludge and ash and the myriad pollutions of the Hive.
However in most cases it would be a lot easier to simply make use of the oceanic surface to capture energy and convert it into sugars and protein - algal mats and so forth are a relatively efficient means of converting stellar energy into "food", harvested and processed into protein mass they would also provide a reasonably low volume, high density means of shipping the "food" to elsewhere. Of course Agriworlds are also reliant on imports, huge volumes of their global carbon and numerous other chemicals leave the planet (in the form of the sugars, starches and proteins they produce) every year and without imported fertilizers, lime...etc their growth medium would very quickly become useless.

So the Librarians are recruited from the Imperium at large, not just the Chapter Worlds...

The problem with that is that almost all of the psykers carried by the Black Ships are too old to accept the implantation required to become Marines and if Librarians aren't implanted and trained like the rest of the Chapter there's little point in not simply attaching Primaris psykers from the Schola to Marine Chapters - if nothing else the latter would save the Chapter from the difficulties involved in training a burgeoning psyker.
The Blood Angels and a few other fluff-breaking Chapters can use those selected from the Black Ships because they have those "devices" which make an adult into a Marine, implanting, conditioning and training them in a very short period of time but the Dark Angels (for example) draw their psykers unknowingly from their seed worlds and have to deal with people like Two Heads Talking who manifest as psykers after they've been implanted and begun training.
Yes it's not impossible (and indeed its hinted at IIRC) that the family line of Two Heads Talking was likely to produce psykers (he was IIRC from a line of shaman (not in the Starchild sense)) and that lines like that are preferred by the Chapter, which would cant the distribution somewhat but it's still insufficient to explain the jump from one in a million to one thousand seven hundred in a million (the 1.7% I quoted earlier).

[Dolnikan]

As a matter of fact, recessive genetic disorders which are rare will receive very low selective pressure and for that reason only genetic drift can take them from the gene pool. Most people carry a few such alleles, but they will almost never encounter a mate carrying another copy of it.  Of course the better known disorders are not that rare, but then again, it helps being more common to attract some attention.
An emerging trait can easily be extremely rare. New traits will always start out immensely rare and will slowly become more prevalent, if they offer an advantage or by chance.

If it is regulated by a signgle gene(I make this assumption to simplify matters a bit, with more regulatory genes would just be a lot more difficult but the basic idea would remain the same.) The gene would have to be recessive because a dominant trait would not emerge in the way it does all over the galaxy, by chance the number of needed mutations would be far too high because it is very rare for a psyker to procreate.

This recessive gene would have started out being immensely rare, only a single copy being present. It has since then spread slowly through the population until the first psykers started to emerge. Being a psyker is quite a selective disadvantage in the Imperium, psykers have a far lower chance of procreation than normal humans. The gene is lucky enough to still be spreading through the population despite its very small overal negative fitness effect. However, if we assign even a small positive effect to the heterozygote, such as being more lucky than usual or anything like that, it will suddenly have an evolutionary advantage and will spread through the population without humanity having to be lucky.
To be emergent psykers even have to be rare, otherwise there would be far more homozygotes who are removed from the genepool by the Imperium. In that case the negative effect of the homozygote starts to have a greater fitness effect than the heterozygote.

If psykers are as common as 1,7% Hardy-Weinberg tells us that about 13% of all people carry the psyker gene. Right now I am too lazy to do the rest of the calculations but they will probably show that the number of psykers should be continually decreasing. A possible reason for the high proportion of psykers in the space marines could be that their geneseed carries something which makes psykers far more common, perhaps even displacing the non-psyker gene with the psyker gene. It could also be something else. The space marines are based on the primarches who are based on the Emperor, who is quite a psyker himself.

All this of course depends on one fatal error I made, trying to insert some logic into 40k.

I am sorry for not writing as clearly as I should, I missed sleep tonight.

[MarcoSkoll]

A recessive trait isn't the same as an emergent one though (and even so I can't find a congential defect with anything close to a one in a million risk).

I estimated conscious psychic control at more like one in hundreds of thousands, rather than millions. (Given that the one in a billion figure refers to exceptionally powerful psykers). There are going to be a lot more latent psykers who don't realise their potential.

And there are genetic conditions with about that kind of rarity. Pentasomy (An individual with five sex chromosomes) is about one in a hundred thousand.

To say that Humanity is an emergent psychic race based on a one in a million incidence is...

...to say that the percentages are small, but statistically increasing.

To say that one in a million can't mean a psychic race isn't that different to saying the Earth isn't home to intelligent life. Intelligent (even sentient, in its literal meaning) organisms are outnumbered by many more orders of magnitude than six by the unintelligent ones, despite all Terran flora and fauna having the same abiogenetic origin.

(incidence of red or ginger hair is also greater than one in a million, and that's globally).

Bugger, I thought I was one of less than seven thousand people with red hair. I am no longer unique.

[DapperAnarchist]

Why would almost all of those psykers be too old? The Black Ships take EVERY psyker they can find, from babes in arms to nonagenarians. Further, on a normal Imperial world, there will be more young active psykers than old ones as the witchhunts won't have found them yet. So I'd assume that a Black Ship would contain a large number of young psykers (5-25, assuming those younger are mostly latent) and a few older ones (shamens, witch-women, that sort of thing). A quick detour to the nearest Chapter World every half-dozen sectors would seem to me to be enough to provide the Chapters with what they need. And thats before suggesting that perhaps Psykers accept the implants better (being closer in many ways to the original Primarchs), or that the process might be more closely observed for Psykers, as they are a rarer and more powerful resource, or that the Librarium includes a number of Brothers who are not combat-able, but provide psychic support and record keeping.

As for the idea that humanity should be losing its psychic tendency - the Warp is pushing humanity towards psychic ability. Why? Who knows. The Starchild, or the Chaos Gods, or even that old classic, a C'Tan Did It, or some combination of all of those and more (Eldar, Old Ones, Dark Age gene-altering, Fate). Personally, I go for the all those and more - humanity's future is a battlefield between gods.

[InquisitorHeidfeld]

Let's start trying to pull together conclusions from this lot (if for no other reason than it's starting to get confusing to try to put together arguments to, and respond to arguments from, three people simultaneously).

For a start we can all agree that the 1.7%, Librarians as a portion of a Codex Chapter is far in excess of the galactic average – especially given that they would represent the most powerful psykers rather than the totality.
Originally of course a Chapter's Librarians weren't explicitly psykers so I think we'd be safe to conclude that the source of those numbers was one of the writers posing the question of how many Psykers would be reasonable to ensure a Chapter's self sufficiency without reference to the Galactic norm (another incidence of not understanding the numbers).

Now how this comes about is another matter.
To assume that it's down to Geneseed is to misunderstand what Geneseed is.
Geneseed is grown in the Progenoid glands of a mature and fully implanted Marine, the Progenoids store up Geneseed which is then used to grow the zygotes which, after implantation, develop into the organs which make a Space Marine. (Which, incidentally, makes the idea of the Tyrant Guard being made from Space Marine DNA erroneous, a Space Marine is genetically unchanged by the implantation (perhaps that's different with the "instant Marine" Chapters)).

However we know that the incidence of a gene is not equivalent to the incidence of the trait for which that gene codes and, to my knowledge, Psykers express around puberty therefore we may conclude that it's possible that the Psyker gene is "activated" by hormone levels (low or high, a particular balance...) so it is possible that the actions of the growing zygotes, the accompanying drug, hormone, hypno...etc therapies or some other factor in the early life of a Marine increases the chances of the Psyker gene expressing.

The expression of the gene before puberty would, to my knowledge, be incredibly unusual... but incredibly unusual is not necessarily a bar to that as a solution. The Black Ships need only provide seventeen thousand psykers to the Marine Chapters per generation to fulfil that 1.7% "requirement" and with (from previous assumptions) 900 billion to choose from that's far from unachievable.

I still prefer to think of Seed World psykers as the norm but that's based more on the aesthetics, rather than the practicalities, of the matter.


If the incidence of the Psyker gene is higher than the incidence of its expression (ie: If all psykers have the psyker gene but not all people who have the psyker gene are psykers) that provides answers to two other issues. For a start, the psyker gene can be passed on by non-psykers but more importantly it means that there is no hard and fast method for identifying a psyker.
At a certain power level it would be reasonable to assume a sort of call and responce check by another psyker but below that level, those psykers who "cannot channel enough to light a candle" migh well be missed. Their capacity is minimal, insufficient to pose a danger perhaps... But just perhaps they have hair-trigger neck-hairs (they're telepathic and just strong enough to pick up a "killer intent" from someone near them), maybe they're a little less susceptable to industrial accidents...etc.
Suddenly there is a positive evolutionary pressure, below notice but still present, toward psychic ability...

And that's assuming that psykers of the Schola remain celibate - I'm not aware of anything saying they must.



I would still say that the "Perils of the Warp" must, by necessity of numbers, be too rare to be governed by an arbitrary roll in a game like Inquisitor.
The "specialness" of all Inquisitor characters (focus of the story therefore must be special) should (IMHO) manifest itself through the plot rather than a lucky (or decidedly unlucky) dice roll.
However, my conception of the 40k 'verse is based on older background (eg: totally ignoring Tyrant Guards  ).

[MarcoSkoll]

Which, incidentally, makes the idea of the Tyrant Guard being made from Space Marine DNA erroneous, a Space Marine is genetically unchanged by the implantation (perhaps that's different with the "instant Marine" Chapters).

While I don't think it's necessarily the intent, it's easily explained.

- Firstly, Space Marine candidates themselves are genetically superior to just any Tom, Dick or Harry, by virtue of being 10 year old badasses who can take on tests set in the vein of those that the Primarchs took.
- Secondly, one can assume that geneseed, as organic and self-growing machinery, has its own genetics.
- Thirdly, given all the other genetic mashing the Tyranids do, dealing with a genetic chimera (of sorts - I know that's not strictly what a genetic chimera is, but it's a close enough term) like a Space Marine would be absolute child's play.

[InquisitorHeidfeld]

Yes, except that they already do all sorts of modifications, adrenal sacks, hive mind synapses...etc. The sorts of modifications which supposedly set a Tyrant Guard apart were already well within their capabilities and many were already in place.