[N01H3r3]

Well, the Orders Hospitallier have a good knowledge - at least that of a modern doctor, probably much more among the higher ranks...

And Lasguns are produced in Manufactoria on dozens of Hiveworlds across the Imperium. Also note that the Orders Hospitaller make use of faith healing as much as medical science (much as the Orders Militant make use of faith killing alongside their weapons and armour).

IMO, there's a point at which science and technology becomes sufficiently complex that the Mechanicus are the only ones who will legitimately possess the knowledge of it (because they'll hunt you down and salvage your corpse for servitor organs if they don't think you should have it). Modern medicine, the skills of field Medics... that's sufficient for the common man, but the sciences of anagathics (anti-aging treatments), genetic engineering, mind-wiping... those are things that the common man should not know, even if he can afford to procure the services of the Mechanicus to perform those services for him.

[MarcoSkoll]

IMO, there's a point at which science and technology becomes sufficiently complex that the Mechanicus are the only ones who will legitimately possess the knowledge of it

Very much agreed.

It would be pretty silly to suggest that there weren't humans in the 41st millennium who could understand modern medicine or fix a combustion engine. Pretty much anything that could be easily understood by an intelligent human isn't anything the AdMech couldn't maintain monopoly over, so I doubt they'd waste their time with things that mundane.

I mean, eventually you have to draw a line, or it gets to "Oh blast, the light bulb's gone again. Would someone call in a Magos to change it please?"

[Vladimir]

I mean, eventually you have to draw a line, or it gets to "Oh blast, the light bulb's gone again. Would someone call in a Magos to change it please?"

+++NOT VALID, THE CORRECT RITUALS MUST BE MAINTAINED SO AS NOT TO DISHONOR THE MACHINE SPIRIT OF THE LIGHTING SYSTEM+++

Of course, the mechanicus might have trained up some individuals to maintain the lighting (with the proper ceremony and respect for the mysteries of such technology), but the fact remains that these individuals are merely performing rituals taught to them, and may well have little understanding of things like electrical charges.

[N01H3r3]

I mean, eventually you have to draw a line, or it gets to "Oh blast, the light bulb's gone again. Would someone call in a Magos to change it please?"

+++NOT VALID, THE CORRECT RITUALS MUST BE MAINTAINED SO AS NOT TO DISHONOR THE MACHINE SPIRIT OF THE LIGHTING SYSTEM+++

Of course, the mechanicus might have trained up some individuals to maintain the lighting (with the proper ceremony and respect for the mysteries of such technology), but the fact remains that these individuals are merely performing rituals taught to them, and may well have little understanding of things like electrical charges.

Something covered by the 'lay-technician' concept I tend to use - men and women taught particular rituals crucial for the function of a machine but to mundane for even a lowly Enginseer to bother with - and by the Trade (Technomat) skill in 40kRP (which covers rote-learned care and maintenance of devices, compared to Tech-Use which covers actual technical ability and understanding).

Of course, how much the person knows will vary from world to world and culture to culture - someone from a Hive World or who grew up on starships is likely to be far more familiar with technology than most, for example. More important, really, is the end result of that knowledge - so long as they do the right things and come to all the right conclusions at the end of it, does it really matter whether they're "appeasing the spirit of the machine" or just cleaning a lasgun? At the end of it all, the difference is one of belief - the guardsman will still clean his lasgun regularly, whether he understands the technical reasons for it or simply doesn't want to annoy the gun's spirit. And, if he fails to do so, the  weapon's function will be impaired - again, whether he believes that he's angered the spirit for failure to perform the correct rituals or understands that he's just got dirt in the workings and needs to give it a proper clean.