Zone of Truth + Detect Thoughts

[Dalinar]

Zone of Truth specifies that an affected creature cannot speak a deliberate lie while in the zone.

Detect Thoughts, as the name implies, lets you read minds.

(Before you say anything, our DM ruled that the two spells work together--personally, I'd have leaned on the word "speak" and shot it down, given the situation at hand, but he likes to encourage creativity, so...)

Our DM presented us with an assassin, who we took prisoner and managed to prevent from suicide pilling. He appeared unable to speak, and definitely wasn't right in the head--his eyes fluttered around the room (an Insight check revealed that this was tactical analysis) and then stared straight into nothingness. No outside stimulus seemed to affect him, including every language we knew, threats of violence, some actual violence--even the Command spell didn't do a whole lot productive.

So we had someone cast Detect Thoughts.

Turns out this guy can only think in numbers.

Now, it occurred to me that pretty much anything in the world can be expressed in numbers with a little creativity. Computers existed at one point in this setting (there was an apocalypse, blah blah blah, not the point), so it stands to reason that the idea of binary exists. So, after someone also cast Zone of Truth just to be sure, I said:

"Zero equals false, one equals true. Are you being controlled by an outside force?"

We got a zero, followed by a pause, followed by a stream of binary gibberish. Guy seems to have figured out that babbling incoherently is how you get around Zone of Truth. Neat.

So after a few more questions, I had this bright idea: "I will interpret gibberish as a 'yes'."

DM ruled that that didn't work, and cut the encounter short as he felt there'd be rather extreme worldbuilding implications if a combination of two 2nd-level spells could be used to interrogate someone in that fashion. Fair enough--I've played with the guy for a decently long time and I don't think I've ever seen him stumped like that before.

But I'm very curious how YOU, dear reader, would have handled that situation, as a player or as a DM. As mentioned, I'd probably just rule that the two spells don't work together like that, in retrospect. Alternative solutions: some amount of psychic damage (a la Geas), temporary unconsciousness (as the prisoner is rendered unable to think at all), or maybe some other weird consequence?

[GreyBlack]

Zone of Truth specifies that an affected creature cannot speak a deliberate lie while in the zone.

Detect Thoughts, as the name implies, lets you read minds.

(Before you say anything, our DM ruled that the two spells work together--personally, I'd have leaned on the word "speak" and shot it down, given the situation at hand, but he likes to encourage creativity, so...)

Our DM presented us with an assassin, who we took prisoner and managed to prevent from suicide pilling. He appeared unable to speak, and definitely wasn't right in the head--his eyes fluttered around the room (an Insight check revealed that this was tactical analysis) and then stared straight into nothingness. No outside stimulus seemed to affect him, including every language we knew, threats of violence, some actual violence--even the Command spell didn't do a whole lot productive.

So we had someone cast Detect Thoughts.

Turns out this guy can only think in numbers.

Now, it occurred to me that pretty much anything in the world can be expressed in numbers with a little creativity. Computers existed at one point in this setting (there was an apocalypse, blah blah blah, not the point), so it stands to reason that the idea of binary exists. So, after someone also cast Zone of Truth just to be sure, I said:

"Zero equals false, one equals true. Are you being controlled by an outside force?"

We got a zero, followed by a pause, followed by a stream of binary gibberish. Guy seems to have figured out that babbling incoherently is how you get around Zone of Truth. Neat.

So after a few more questions, I had this bright idea: "I will interpret gibberish as a 'yes'."

DM ruled that that didn't work, and cut the encounter short as he felt there'd be rather extreme worldbuilding implications if a combination of two 2nd-level spells could be used to interrogate someone in that fashion. Fair enough--I've played with the guy for a decently long time and I don't think I've ever seen him stumped like that before.

But I'm very curious how YOU, dear reader, would have handled that situation, as a player or as a DM. As mentioned, I'd probably just rule that the two spells don't work together like that, in retrospect. Alternative solutions: some amount of psychic damage (a la Geas), temporary unconsciousness (as the prisoner is rendered unable to think at all), or maybe some other weird consequence?

As a DM, personally, my rule of thumb is that you never give the players access to information that you don't want them to have access to. If the DM didn't want you to know who he was working for, then I might have (instead of a suicide pill), ruled that some type of bomb was implanted in the assassin, and that as soon as he noted that he was being controlled by an outside force, it would have detonated. Now, the PC's know that they're dealing with some type of cult who are willing to implant bombs in their assassins to prevent them from divulging information. And, from there, the PC's might have gone down that rabbit hole to see what's going on.

Alternatively: He was being compelled, but he didn't really have any knowledge of who he was being controlled by. Just because you're being controlled doesn't mean that you know who is controlling you. That, or he just doesn't know motives or anything.

That said, I'd totally reward your creativity in this situation, and maybe even reward Inspiration for thinking outside the box.

[Darth Credence]

First, I would absolutely rule that they can lie in their mind. Since Zone of Truth allows for people to either not answer, or come up with an evasion that is still technically the truth, I don't see how you can square that with not being able to think a lie.
But if we get past that, I would not rule that the numbers had anything to do with it. The spell detect thoughts implies, IMO, that there is no language barrier. If the target speaks a language, the spell can work on them. Not if they speak a language the caster speaks, just a language, so I interpret it as the meaning comes through, not just words. This also makes sense to me as not all people think with an inner monologue that has words.
As to how to deal with "I will interpret gibberish as a yes", my thought as the DM would be you can interpret gibberish in any manner you want, that doesn't mean that they can't respond with gibberish when the answer is no, or for that matter that 0 is no or 1 is yes. If to them, 0 means yes and 1 means no, then you interpreting it backwards is on you, not them. They wouldn't be lying. And I would not tell the player that. (This is all assuming, of course, that I had already agreed to the previous bits that I wouldn't have agreed to.)
I would also, if running the NPC, have them simply repeating a song in their mind over and over. Nothing about zone of truth forces someone to answer a question, and if someone ignores any questions and simply repeats something in their head, that would beat ZoT. Detect thoughts will direct people to think a specific way, and is normally worthwhile in interrogation, when the person being interrogated doesn't know detect thoughts is active. Because the answer to how do you not think of a polar bear can easily be to concentrate on something else intensely enough that there is no room to consider a polar bear.

[Narsham01]

Two possibilities:
1. You weren't supposed to catch and interrogate this guy and your GM is throwing out improvised explanations for why you can't get any information out of him. That's unfortunate, because you should receive some reward for doing the unexpected successfully.
2. This guy's characteristics are important/vital details in the GM's world, so even getting concrete details on how this assassin order trains its agents should be extremely valuable and have use for you in the campaign. In that case, your creative solution didn't get you what you wanted, but it got you something of value, and this was well done. (For example, you may have just learned this world still has replicants/androids and that this order of assassins uses them.)

As for the spell combination: Zone of Truth does not compel answers, it just says that if you speak, you cannot deliberately lie. An assassin in a fantasy world prepared as this one seems to have been would definitely be prepared for a relatively common L2 spell, so even if ZoT compelled truthful thoughts, because it cannot compel a response at all, the assassin shouldn't have thought anything in response to the prompts and questions. If you slipped one past and got an answer, that might be the other reward here.

In short: the two spells shouldn't interact except that you can get the thoughts of a person who is refusing to answer. Even then, at surface level, I'd rule that you're more likely to get "I can't tell them that" as a thought than "Don't say revenge, don't say revenge, don't say revenge" because someone determined to conceal something isn't inevitably going to think of that thing directly in response to questions.

[kazaryu]

Zone of Truth specifies that an affected creature cannot speak a deliberate lie while in the zone.

Detect Thoughts, as the name implies, lets you read minds.

(Before you say anything, our DM ruled that the two spells work together--personally, I'd have leaned on the word "speak" and shot it down, given the situation at hand, but he likes to encourage creativity, so...)

Our DM presented us with an assassin, who we took prisoner and managed to prevent from suicide pilling. He appeared unable to speak, and definitely wasn't right in the head--his eyes fluttered around the room (an Insight check revealed that this was tactical analysis) and then stared straight into nothingness. No outside stimulus seemed to affect him, including every language we knew, threats of violence, some actual violence--even the Command spell didn't do a whole lot productive.

So we had someone cast Detect Thoughts.

Turns out this guy can only think in numbers.

Now, it occurred to me that pretty much anything in the world can be expressed in numbers with a little creativity. Computers existed at one point in this setting (there was an apocalypse, blah blah blah, not the point), so it stands to reason that the idea of binary exists. So, after someone also cast Zone of Truth just to be sure, I said:

"Zero equals false, one equals true. Are you being controlled by an outside force?"

We got a zero, followed by a pause, followed by a stream of binary gibberish. Guy seems to have figured out that babbling incoherently is how you get around Zone of Truth. Neat.

So after a few more questions, I had this bright idea: "I will interpret gibberish as a 'yes'."

DM ruled that that didn't work, and cut the encounter short as he felt there'd be rather extreme worldbuilding implications if a combination of two 2nd-level spells could be used to interrogate someone in that fashion. Fair enough--I've played with the guy for a decently long time and I don't think I've ever seen him stumped like that before.

But I'm very curious how YOU, dear reader, would have handled that situation, as a player or as a DM. As mentioned, I'd probably just rule that the two spells don't work together like that, in retrospect. Alternative solutions: some amount of psychic damage (a la Geas), temporary unconsciousness (as the prisoner is rendered unable to think at all), or maybe some other weird consequence?
so...im confused. if you interpret 'gibberish' as 'yes' why would that not work? thats...i mean that just you making an assumption, which you should be allowed to do. why does the DM care if you make an assumption? ironically, i assume that im missing something, i just...don't understand the problem.


for my part, i don't treat 'surface thoughts' as being that easy to control. like, you can, in fact, think of ways to get around telling the true. As per the zone of truth spell. But such thoughts are also going to get detected by the detect thoughts spell. Even the spell itself says that its a powerful tool for interrogation. So, for someone to control their 'surface thoughts' to the point that they'd be able to obscure them from a detect thoughts spell, i'd probably have an opposed check. something like intelligence or cha (for the victim) vs wisdom (for the interrogator). and even then, only if the person being interrogated is actively trying to avoid having their mind read.

[Valmark]

Zone of Truth specifies that an affected creature cannot speak a deliberate lie while in the zone.

Detect Thoughts, as the name implies, lets you read minds.

(Before you say anything, our DM ruled that the two spells work together--personally, I'd have leaned on the word "speak" and shot it down, given the situation at hand, but he likes to encourage creativity, so...)

Our DM presented us with an assassin, who we took prisoner and managed to prevent from suicide pilling. He appeared unable to speak, and definitely wasn't right in the head--his eyes fluttered around the room (an Insight check revealed that this was tactical analysis) and then stared straight into nothingness. No outside stimulus seemed to affect him, including every language we knew, threats of violence, some actual violence--even the Command spell didn't do a whole lot productive.

So we had someone cast Detect Thoughts.

Turns out this guy can only think in numbers.

Now, it occurred to me that pretty much anything in the world can be expressed in numbers with a little creativity. Computers existed at one point in this setting (there was an apocalypse, blah blah blah, not the point), so it stands to reason that the idea of binary exists. So, after someone also cast Zone of Truth just to be sure, I said:

"Zero equals false, one equals true. Are you being controlled by an outside force?"

We got a zero, followed by a pause, followed by a stream of binary gibberish. Guy seems to have figured out that babbling incoherently is how you get around Zone of Truth. Neat.

So after a few more questions, I had this bright idea: "I will interpret gibberish as a 'yes'."

DM ruled that that didn't work, and cut the encounter short as he felt there'd be rather extreme worldbuilding implications if a combination of two 2nd-level spells could be used to interrogate someone in that fashion. Fair enough--I've played with the guy for a decently long time and I don't think I've ever seen him stumped like that before.

But I'm very curious how YOU, dear reader, would have handled that situation, as a player or as a DM. As mentioned, I'd probably just rule that the two spells don't work together like that, in retrospect. Alternative solutions: some amount of psychic damage (a la Geas), temporary unconsciousness (as the prisoner is rendered unable to think at all), or maybe some other weird consequence?

I wouldn't let them work together- you're not forced to think true by a spell that compels you to speak the truth.

That said- echoing others in saying that the end was weird. If you told me 'I'll interpret X as yes' my reply would be 'sure' as it doesn't mean the target will be compelled to only say X while meaning yes.

For that matter also saying '0 is false 1 is true' wouldn't have worked had it been me- they're gonna reply in their language and if you give their words a different value (let's say 0 is true in binary) they'll still reply 0 when it's true, even if you said that 1 is true.

[Lunali]

There's a lot of implications if you let zone of truth force people to stop lying inside their own heads. The two spells working together only makes sense if you assume that this is the case, which means that while the assassin is the only one getting their thoughts read, the entire party has to tell the truth to themselves about whatever they happen to think about.

The more interesting combination IMO, which actually works by RAW, is speak with dead and zone of truth. Speak with dead actually compels the target to answer the questions and zone of truth forces them to tell the truth.

[Darth Credence]

There's a lot of implications if you let zone of truth force people to stop lying inside their own heads. The two spells working together only makes sense if you assume that this is the case, which means that while the assassin is the only one getting their thoughts read, the entire party has to tell the truth to themselves about whatever they happen to think about.

The more interesting combination IMO, which actually works by RAW, is speak with dead and zone of truth. Speak with dead actually compels the target to answer the questions and zone of truth forces them to tell the truth.

Doesn't work. Zone of truth works on creatures. Corpses are objects. Speak with dead always calls what you are speaking with a corpse.

[Valmark]

Doesn't work. Zone of truth works on creatures. Corpses are objects. Speak with dead always calls what you are speaking with a corpse.

That is not necessarily true- after all you're reanimating a corpse, it's not particularly different from an undead. I wouldn't say it works without room for interpretation, but I also wouldn't say that it doesn't (and personally I go with the second interpretation).

[Darth Credence]

That is not necessarily true- after all you're reanimating a corpse, it's not particularly different from an undead. I wouldn't say it works without room for interpretation, but I also wouldn't say that it doesn't (and personally I go with the second interpretation).

You don't reanimate the corpse for speak with dead, and speak with dead doesn't work on anything that is undead. A corpse is an object, according to Crawford as seen at this page: https://www.sageadvice.eu/corpse-creature-or-object/
Zone of truth only works on creatures.
By RAW, zone of truth does not force the object of speak with dead to answer honestly.

[firelistener]

The DM obviously didn't intend for you to be able to capture him and interrogate him so thoroughly, thus the struggle with rulings. I did that sort of thing early on, but I've learned to just let players "win" in that scenario because coming up with technicalities to counter their plans just teaches them not to try anything clever again. Running the game is hard, so while I do think your DM kinda flubbed the situation, I also suggest letting it slide.