How can I apply subjective morality to Starfinder?

[MonkeySage]

In a game where you can tell someone is "Evil" just by casting a spell, how can I remove such spells when I'm encountering resistance from some of my players?

This is a setting where "Good" and "Evil" are mortal concepts, which higher beings just don't understand. Spells that identify someone's alignment just don't exist in this setting. The worst tyrant still believes they are acting in the best interests of their people. The beings mortals call "Demons" are just beings that believe creation of the mortal plane was a mistake.

[Andor13]

I don't understand the question. If you're the Gm and you don't want the spells, remove the spells.

If your players insist and you allow it, subvert their expectations that these spells function as "Detect Plot." Their boss detects as evil. The "bad guy" detects as good. In both cases it's just residual traces of tiefling/aasimar blood from when that meant something before the setting shift.

[Ilorin Lorati]

You can probably pull some of the alternative alignment rules (http://paizo.com/pathfinderRPG/prd/unchained/gameplay/removingAlignment.html) from Pathfinder Unchained with little to no work, if you want something a little more substantial than "Nah, they don't exist."

[Tectorman]

The wonderful thing about Starfinder is that while alignment technically exists, it is as easy to utterly ignore as saying "Opt out".

As far as I know, the game does not even have "Detect Alignment" spells, so I'm not sure by what means anyone can tell you're evil for casting an evil spell. For that matter, the only spell in the core rulebook that even has a descriptor is Planar Binding, and even then, the core rulebook doesn't actually say what a spell having an alignment descriptor means. Which means using Planar Binding to summon a devil might as well have the "Chariot" and "Bacon" descriptors. There is no Horror Adventures for Starfinder or any other such sourcebook that actually says casting a spell with the "Evil" descriptor counts as an evil act; furthermore, as page 25 says ignoring alignment is supposed to be easily achievable, they can't release such a book.

So if you don't want alignment to mean anything in Starfinder, then it doesn't. Truly they were as saints who put that "Opt out" feature in this game.

[Esquire]

Just make it so that detect x spells key off of the target's self-image. The spells are now almost completely useless; your players will stop casting them after it returns the oppressive government agent as Lawful Good simply because he sees himself as serving a necessary source of order in society (or whatever).

[Arutema]

In a game where you can tell someone is "Evil" just by casting a spell, how can I remove such spells when I'm encountering resistance from some of my players?

This is a setting where "Good" and "Evil" are mortal concepts, which higher beings just don't understand. Spells that identify someone's alignment just don't exist in this setting. The worst tyrant still believes they are acting in the best interests of their people. The beings mortals call "Demons" are just beings that believe creation of the mortal plane was a mistake.

As other posters have pointed out, there are no alignment-detection effects or spells in Starfinder.

There are fusions in the core book that ignore the DR or resists of specific-aligned dragons or outsider. These could easily be replaced with fusions that ignore all resists of dragons or outsiders regardless of alignment.

I think there is an archetype in Pact Worlds that gives a weak form of smite. You could probably just strip this ability from the archetype.

And drop the one-step rule from the Priest theme, if anybody feels like taking it.