Good, Evil - I'm the Guy with the Gun

My 150th post!
Sorry for the light posting, but (as mentioned often before) this is a very busy time of year for me.

  So a question came up recently from an email correspondent. To wit, how much would Detect Evil and Know Alignment change laws and society?

  Tough question. Let's look at some spells and their descriptions and see what we can figure out.

  Detect Evil seems fairly straightforward. 1e says,

  "This is a spell which discovers emanations of evil, or of good in the case of the reverse spell, from any creature or object. For example, evil alignment or an evilly cursed object will radiate evil, but a hidden trop or an unintelligent viper will not."

  And OSRIC says,

  "This spell allows the cleric to discern emanations of evil (or good, in the case of the spell’s reverse) within the spell’s area of effect, a beam-like pathway. The spell detects evil, not danger, so it will be useless to discover such things as a mindless trap or a poisoned wineglass."

  But! The DMG (1e) (of course) says on page 60,

  "Only a know alignment spell can determine the evil or good a character holds within... ...Characters who are very strongly aligned... and are of... at least 8th [level]... might radiate evil..." [emphasis added]

  It goes on to say,

  [paraphrase] 'Aligned undead, creatures such as Ki-rin, and the like will radiate evil or good; aligned magic items will likewise radiate evil or good'.

  So, combined with the rest of the section, Detect Evil can only detect active evil intent unless the target is really, really bad. A vampire lurking in wait for a victim? Bam! Strong, malignant evil detected! A goblin frying up a mouse fritter? Detect Evil isn't going to pick him up. A goblin waiting in ambush? Faint, lurking evil. Why faint? it's only a wee goblin.

  So Detect Evil isn't 'bad guy radar', but more a 'shambling horror detector' combined with (mentioned earlier) an 'evil intent sensor'.

  So it seems that Detect Evil, while obviously useful, isn't going to change the laws or society very much at all. While very useful for paladins and clerics trying to locate a ghoul or avoid an ambush it has little practical use in day to day life.

  Taking a little detour, we need to also look at the Fourth level spell Detect Lie. What I find fascinating here is that the existence of this spell implies, strongly, that Detect Evil can't detect when you are lying! Since the spell description in the DMG on Detect Lie mentions that the spell can not detect 'evasions' but only direct lies and the level of the spell is very high this implies that lies are evil but subtle enough to the point a specific spell is needed and, even then, only direct falsehoods can be detected.
  It seems obvious that Detect Lie would have a huge impact on the law: interrogations could, in the hands of skilled interrogator with this spell, quickly identify lies (if not necessarily revealing the truth!) But, of course, you need a 7th level+ cleric (or an 8th+ level religious brother) and a typical medieval kingdom 1s going to have, oh, at most five people who can cast the spell, and all of them are going to be rather prominent members of the community, i.e., either very busy, very expensive, or both. And they would have to give up access to spells like Exorcise to learn Detect Lie instead. Oh, and getting two different people to cast it to confirm each other might be effectively impossible, so it might boil down to a mere claim by the caster!
  So while Detect Lie might make a big difference in very important matters (the death of a king, the theft of an artifact, etc.) it will be very unlikely to be available for routine work.
  So - very little impact on laws or society.

  Finally, we are at Know Alignment which, the rules say,

  "...enables the cleric to exactly read the aura of a person - human, semi-human, or non-human. This will reveal the exact alignment of the person. Up to 10 persons can be examined with this spell."

  "This will reveal the exact alignment..." That is very, very clear, isn't it? There are a fair bit more people who can cast Know Alignment - at least 20 and, if you are using Religious Brothers and counting higher level casters, more like 100! So a fair number of people are going to be able to determine if you are a bad guy or not.
  Now, I have heard many a person say that casting Know Alignment on MPCs is 'rude', or 'improper', or 'forbidden', but I was never sure where this came from. The 1e DMG says on page 35,

  "...it is considered poor manners to enspell [a potential henchman] in any way (except possibly in the case of Know Alignment..."

  So it seems obvious that senior officers, etc. should expect to have their alignment checked at least at the time of employment. Indeed, I personally assume any spellcaster or group that can  cast spells like Know Alignment, Detect Charm, Detect Curse, etc. will cast them on their henchmen and hirelings from time to time.

  This will change society and the law, at least a little. It will be much, much more difficult to insert a mole into an organization, replace someone with a doppleganger, etc. if routine use of these divinations is a part of your campaign.
  Although it explains a lot about the use of assassins to spy from the 1e DMG! With their use of alignment tongues, disguises, etc. I have always assumed that the spying charts is also the chance the assassin successfully dodges these spells.
  This also makes items like Rings of Mind Shielding and Amulets of Proof vs Etc., Etc. more valuable.
  So at first glance it seems obvious that Know Alignment should have a huge impact on your campaign world.
  My next article will explain why it won't!