All Acolytes and Inquisitors have "philosophies" - that is, belief systems that they adhere to and extremes they will or will not cross.

The fact that an Inquisitor (who is often otherwise all-knowing or a master planner) could cobble together a Cell of Acolytes that is likely to succumb to infighting or even potentially revolt against him seems a bit iffy to me.

I'm not only talking about the classic "Witch-hating firebrand Cleric and Radical Psyker" combo or "Monodominant Acolytes rebel against their Radical master", but PCs who are likely to commit tech-heresy, ally with Xenos, or succumb to one of the heresies that seems so normal in the real world like Ateanism, the Logicians, or Recongregator philosophies.

This is an argument I have been having with one of my players - help me find reasons why an Inquisitor would not also handpick his Acolytes depending on their philosophies as well as their skills!

All I have right now is that Radicals might pretend to be Puritains at first, and trust the Grimdark galaxy and the passage of time will change their views to his advantage. But it is also known that Monodominants do the same (as they trust that time will convert others to their philosophy as they realise how unimportant a life is when weighed against their Holy mission), so that seems like a weak argument.

I've been asking myself the same thing for long. My answer was this:

-Either you tell your players what should be the "general" mentality of the groupe or you ask what it must be, explaining them the different possibilities.

My campaigns are set in my own alexverse where the principal inquisitors and other great powers of the Empire are recurring characters. Players learn to know about this and developp their characters in consequences.

This is something that needs to be discussed with the group during character creation. If a player has a character idea that will not work with the group, the GM should reject the character. Preferably before anything is written on the character sheets.

Just another reason why setting the entire first session aside for character creation is a good idea.

One way to get around it is based on the lore of Askellon - it is strongly implied that there are few Inquisitors in the sector, possibly only a handful. There is a lot of ground to cover, so each would logically have quite a large network of Acolytes to do the majority of the work. It is feasible that in delegating so much to Interrogators, an Inquisitor could fail to notice whether or not Acolyte #293 in Cell 34 follows his beliefs to the letter.

That's an other valid point of view.

Generally an Inquisitor recruits members to their cause based on a moment of service. They may be chasing the same perp, they might uncover some damning info that the Inquisitor is looking for or just wrong place wrong time. Seldom does an Inquisitor conduct a thorough background search on each and every Acolyte. They likely know "This woman was in a penal colony for murder of an official" and "This g uy was assigned to this data stack as part of a redistribution of labour". They don't get immediate access to inside their Acolytes skulls. If a player decides that their Character is/will become a radical and there's something in their backstory that supports this, there's a chance the Inquisitor knows.

But Inquisitors can't (accurately) read the future, and surprises keep an Inquisitor on their toes.

Just another reason why setting the entire first session aside for character creation is a good idea.

I agree with this wholeheartedly. Dark Heresy, perhaps more than many other roleplaying games, is a game in which character interactions are key. If you want to have the kind of inter-party conflict described in the OP, you need to discuss it carefully during the character gen process. If you want to avoid it, then create characters accordingly; not every character concept fits in every game and any dissonance needs to be accounted for and considered. As such, you also need to discuss with the GM what sort of Inquisitor you've been recruited by, the style of play you want and so on and so forth. It's perfectly fine to have a character that is at odds with other PC's, his Inquisitor, the game style or whatever. You just need to bear in mind that A)it might not be as fun always being the outsider and B)the other players might not appreciate you constantly throwing the proverbial spanner in the works.

The easy explanation is that the Inquisitor wanted variety among his acolytes in order to have a team that could approach a variety of problems from a variety of angles - likely with the idea that he could mind cleanse or purge the acolytes if they crossed too many lines.

If the Inquisitor is himself a radical (including a radical Puritan), then his own extreme viewpoints would likely preclude using acolytes who violate his world-view. You might need to adapt your vision of the Inquisitor to fit the party, rather than the other way around. Of course, you could well have an Inquisitor who is explicitly planning on eliminating the acolytes, maybe even sooner rather than later. He might see it more as delayed execution of heretics while using them for his own ends rather than recruiting them in good faith.

i have found out that conflict between the pc or the inquisitor is usually for experienced players. you should avoid it if your players are new to roleplaying. see if they can distinguish role playing from having fun on the table. in my group they plot against each other, the inquisitor and basically everyone but its what they like to do. so i encourage this kind of play by giving them more dilemmas and plot twist. i run a puritan inquisitor so they usually have to hide their radical views. but in the end they are having fun. dont be afraid to change your inquisitor to the players style. just remeber that he is still their master and a personna with great influence and experience. kinda like a corrupted politician. there is reason for him being the inquisitor. he could even assemble a party with diffrent views from himself only to have an escape goat!!

You're are basically talking about alignment. It's hard to get players to agree to that unless they are into the idea. Everyone gravitates toward murder hoboism.

It might be best to go with an Inquisitor is a bit radical. One who is willing to tolerate quite a lot from the acolytes because he/she only sees them as disposable tools. If they keep solving problems the Inquisitor doesn't care how puritan or radical they are. If they look like they might cause more damage than they prevent, then it's time to put them down because they have outlived their usefulness.

The only time this Inquisitor cares about how puritan or radical they are is if it's leading to too much infighting and the Inquisitor believes that if the infighting is stopped then the survivors will still be useful.

As for how the Inquisitor presents him/herself to the party, some Inquisitors put on various personas to infiltrate and/or manipulate others. The one shown to the party could just be another persona. Leading to a possible plot where a rather puritan acolyte cell comes into conflict with a radical one. Catch it, they are both working for the same Inquisitor.

At the start of the game the best way to deal with this is to give the players a general direction of how the campaign should play out, either puritan or radical. Maybe even choosing one of the subfactions. I personally show my players, in game, how their inquisitor behaves in certain situations. That way they get to know him and what he thinks is right or wrong. If they decide to follow that is another thing.

Bear in mind that your players personalities will evolve thru play. An acolyte that started a pure Amalathian might move towards other doctrines over time, perhaps even turning radical or puritan over time due to events in game.

In my current game i have a player that is on the brink of going radical because he feels that the means that the Imperium gives him are insufficient (Yeah i know, HERESY!). This character started as neutral and decided overtime and as he grew more knowledgeable in the ways of the Inquisition to become an Amalathian, but as things went down he is losing his faith that the enemy can be defeated without using the same tools they use.

On the other hand i have a player that also choose to become an Amalathian (probably due to the views of the Inquisitor) and that is starting slowly to become a Monodominant.

In my opinion, if things develop organically in a Dark Heresy campaign you will never have a group that will be completly set in one puritan or radical Doctrine. You just need to be careful to notice when the opposing ideas are about to clash, because in this case there is a good chance that one of the players will die, maybe even at the hands of one of their friends.