How to deal with recording lexical knowledge gained from temporary skills?

Question

There are a couple of skills in D&D which appear to represent your character's lexical knowledge (as opposed to "doing" skills). For example:

Arcana. Your Intelligence (Arcana) check measures your ability to recall lore about spells, magic items, eldritch symbols, magical traditions, the planes of existence, and the inhabitants of those planes. (PHB p.177)

The way this is often played is that the GM will make you roll a check when you want to recall such knowledge, with the DC set according to how common that knowledge is.

But then we also have things like this:

Channel Divinity: Knowledge of the Ages Starting at 2nd level, you can use your Channel Divinity to tap into a divine well of knowledge. As an action, you choose one skill or tool. For 10 minutes, you have proficiency with the chosen skill or tool. (PHB p.59)

Is it therefore possible for a character with no Arcana skill to use this feature, write down all the things they can recall about let's say various potions, then access that knowledge later by just reading their own notes?

It's not a game breaker, it just feels a bit weird. Especially if, like many GMs, your GM rules that you can't even roll a check for a highly specialised skill like Arcana without proficiency.

Answer 1

There are no rules around this

As you've noticed, the rules are only around granting proficiency under certain defined circumstances, not about what happens if you try and record any knowledge gained from temporary proficiencies.

That leaves what to do entirely up to the DM.

Things to consider

Ongoing Proficiency

If you were to grant proficiency moving forward on Arcana checks, you've granted them a de facto proficiency moving forward - and that doesn't seem right.

Situational Advantage

You could offer situational Advantage based on what the character remembers and why. I use this quite often for my players - and it allows them to give some more life to their characters in key situations where it matters and where it can make encounters more interesting.

Other players' characters

One more huge consideration are the abilities of the other characters and the issue of stepping on toes.

If a single character is able to effectively become proficient in every skill, then that character easily becomes the primary spotlight simply because they can do anything. This of course will vary by table and player, but the risk here is real - and it's an easy thing to avoid by not granting to this ability more than what it says.

Additional thoughts

But personally, I wouldn't always allow it or make it always on. Whether or not the information you wrote down is applicable will be dependent on the current needs.

Overall, I'm always wary about gaming a feature for much more than it really provides - especially when the risk of overshadowing others at the table is so real.

Answer 2

Yes, it is possible to record knowledge

There is nothing in the rules that forbids you writing down notes, and later referring to them. In 5e, there is also no requirement to be "trained" in knowledge skills to try and make them, as there is in some other systems. For example, you can make a skill check on Intelligence (History), without proficiency, as shown on page 172 PHB:

For instance, if you lack proficiency in the History skill, you gain no benefit from a feature that lets you double your proficiency bonus when you make Intelligence (History) checks.

While you gain no benefit from features that double your proficiency, you still can make the check.

How your DM handles these notes later on, when you try to make a proficiency check with their help, is up to DM judgment. They for example could state the notes have no effect, grant proficiency bonus for this very specific task, give you advantage on the check without proficiency bonus, which would be a standard way dealing helpful circumstances (but, mathematically may be even better than the bonus in early levels depending on the DC), or require that you as the player made notes, and can use them to look up what you recorded, or that no check whatsoever is needed as you wrote it down.

We typically don’t ask for checks to dig up notes, and never had a problem with that. For example, if you learned from a Intelligence (Religion) check if Zombies are vulnerable to holy water or not, and wrote that down, we'd just say you know that now. However, I’d not allow to use notes to get a an added “permanent-on” knowledge skill. Doing so would remove the reason for and invalidate other's investment in learning such skills to begin with. Also note that brewing potions, for example, is not a knowledge skill. There is herbalism or crafting rules for that.

Answer 3

I Would Generally Disallow This

...for several reasons:

First, it just gets cumbersome. I don't want to keep track of what obscure trivia someone's character has written down, and I don't want to make new rules to check whether someone has written down something important, or how long it takes them to pore through their scroll set of conjured knowledge.

Second, it's just clearly not the intent of the abilities. I am not aware of any hint in the rules that these abilities could or should be bootstrapped into permanent or always-on substitutes for skills. And really, that ruling should be enough for a GM with a good group of players to settle the matter.

Third, I just don't think it's feasible. For those who really need a justification, my rationale is similar to this answer, but more absolute: This doesn't work because you're not gaining proficiency in pedagogy or technical writing or the campaign equivalents of those skills.

I, as an expert in my field, can write very terse and perfectly correct answers to questions in my field. They will be completely unintelligible to people without at least a four-year university degree in my field, probably more.

I can also take take extreme care and write lengthy answers, which avoid technical jargon, add information about edge cases, and fill in what I would otherwise expect to be common knowledge and make things at least somewhat clear to an educated layman. This will take orders of magnitude more time, despite the fact some of my professional duties require me to do just that, and one of my personal hobbies is writing. It can take hours to produce even a short answer at this level of detail. And that's with a word processor.

There are a lot people with my technical skill level who can do the first, but could not do the second if you put their soul in a jar and held it over a bonfire, because they are not skilled writers. It's not their job to be skilled writers, so they haven't achieved any real proficiency.

Ten minutes to randomly start writing useful and accessible information about a professional field? Try it some time and ask yourself how long it would take to produce a university level textbook that way.

Answer 4

Reasoning

The existing answers show us that the game rules don't address the question. One way to handle this is to consider the abstractions that the rules use, and think about how those relate to our own mental processes.

We all have memories of understanding things that we've now forgotten. That seems like a reasonable model for having had a temporary proficiency, but not having it any more. It's also clear that you can write things down while you have a temporary proficiency, but it's not clear what the writings do once the proficiency has gone.

Handling it

The way I'd deal with this case is to consider the information that was written down: not the actual words, which deal with things that aren't real and we can't describe in any detail as players, but its purpose.

What did you write down, and how clearly did you write it? If you just wanted to know a simple specific fact, then sure, you recorded it and can access it later. This is no different from a player taking notes of things that happened in the game.

As for recording a lot of information, that gets harder. The more you try to write down, the more you'll have to use jargon that you understand while you have the proficiency, but probably not afterwards. Thinking you understand the jargon when you don't will likely lead you into utterly wrong information.

If a player wants to exploit this, I'd let them copy from the potion descriptions, or similar rules, writing by hand. I'd limit them to five minutes, because modern paper and pens are a lot easier to use than the typical ones available in the game setting. That will get them descriptions of the things they know about, but it won't get them subtler stuff, like how that potion from this maker generally works fine, but don't eat cabbage after taking it, unless you want to spend the evening throwing up.

Learning

If you can use a temporary proficiency frequently, without anyone getting annoyed with you about it and stopping you, then you can plausibly use that to teach yourself the proficiency. Of course, the DM needs to be happy about that, since it's an extrapolation of the brief rules under "Training" on p. 187 of the 5e Players Handbook, which only cover languages and sets of tools.

It's hard to suggest a general rule about the time and cost, since it will depend on how much of the time you can use your temporary proficiency. If you only have it for ten minutes a day, self-training is going to take longer than if you can use it for ten minutes an hour. You don't have to pay someone to train you, but if using the proficiency requires materials, you'll have to buy those.