# D&D 5EDoes Prestidigitation Break the Law of Conservation of Energy?

#### Levistus's_Leviathan

##### 5e Freelancer
Simple question, but the consequences are a bit strange.

If you use Prestidigitation to clean an object . . . what happens to the "dirtiness" on it? Is it just magically destroyed? Is it teleported somewhere else? Is it somehow melded into the object you clean?

#### Umbran

Staff member
A lot of magic breaks the speed of light (anything involving long-distance messages)

Not as much as you'd think. The speed of light is 300,000,000 meters per second. Given an Earth-sized world, it's circumference is about 40 million meters.

Light can go halfway around the circumference of the world in about 0.07 seconds. If we take "instantaneous" to be less a physicist's "actually zero time", and instead take is as the more practical "less time than you can notice or measure" then the lightspeed barrier is not generally an issue.

#### Umbran

Staff member
We just haven't discovered all the laws, yet! Any sufficiently analyzed magic becomes part of our physics.

Well, no.

If your magic is not repeatable, then analyze it all you want, it won't become part of physics.

#### Maxperson

##### Morkus from Orkus
Not as much as you'd think. The speed of light is 300,000,000 meters per second. Given an Earth-sized world, it's circumference is about 40 million meters.

Light can go halfway around the circumference of the world in about 0.07 seconds. If we take "instantaneous" to be less a physicist's "actually zero time", and instead take is as the more practical "less time than you can notice or measure" then the lightspeed barrier is not generally an issue.
Teleport still breaks it. You can teleport in "less time than you can notice or measure" to a planet in a different solar system. Say from Toril to Oerth. Of course, just because you an break or perhaps bend one law of physics with magic, doesn't mean that you can break or bend all of them. The PHB still says that casters access magical energy through the Weave to create a spell effect, so conservation of energy could apply to all magic.

#### Umbran

Staff member
Teleport still breaks it. You can teleport in "less time than you can notice or measure" to a planet in a different solar system.

Pfeh. The idea that it is in a different solar system in the same contiguous physical space is told to us by some greybeard wizard who has access to no better optics than Galileo had. The view of the "Prime Material Plane" as one physical space is not supported by reproducible data in the hands of mortals in the game worlds in question, and so should be considered suspect.

#### Maxperson

##### Morkus from Orkus
Pfeh. The idea that it is in a different solar system in the same contiguous physical space is told to us by some greybeard wizard who has access to no better optics than Galileo had. The view of the "Prime Material Plane" as one physical space is not supported by reproducible data in the hands of mortals in the game worlds in question, and so should be considered suspect.

Fair enough!

#### Seramus

##### Hero
Well, no.

If your magic is not repeatable, then analyze it all you want, it won't become part of physics.
True! If you don't have sufficient tools to ever succeed at analysis, then you're out of luck. But that's our failing.

#### Umbran

Staff member
True! If you don't have sufficient tools to ever succeed at analysis, then you're out of luck. But that's our failing.

The idea that everything must, and can, be rationalized to "science" is one grounded in OUR universe. But, in our fictional universes, this does not have to be the case.

#### Seramus

##### Hero
The idea that everything must, and can, be rationalized to "science" is one grounded in OUR universe. But, in our fictional universes, this does not have to be the case.
Certainly! An author can always create a magic system with absolutely NO rules.
"Because I said so" is definitely a thing a writer can put into text.

#### Umbran

Staff member
Certainly! An author can always create a magic system with absolutely NO rules.

More importantly - there's a whole lot of space between "absolutely NO rules" and "can be completely systematized". Shades, nuance, and variations are available to us.

#### AnotherGuy

##### Hero

In our next session the PCs will meet Elminster for the first time since they've been in Faerun and one of the party members is an eccentric haughty elven artificer from Evermeet who has had more published papers on numerous topics than Volo, Van Richten and Mordenkainen combined. So among other things, I'm gonna be stealing some of the above posters thoughts for a dialogue between the two.

Below is just a little taste to see with what I’m dealing with at the table, a character prose written by the player.

“Mynx, don’t look at me like that.”
The sphinx construct made a low grinding noise, tilting its head at Fivin.
“Look, when I don’t have to build you out of literal garbage that I found in alleyways I promise you’ll be back to your fabulous self. Right now, though I need to report and beg for funding.” Fivin looked down at the plain clothes he was left with after his disastrous exploration of Undermountain. Fivin was loath to mention it in the company of those other adventurers, but he was almost certain he never owned this slightly stained jerkin, nor the set of pants he woke up in. He sighed. “And now to walk into the Great Library as if I’m a well-to-do academic, and not a plain-clothed wretch with a walking pile of garbage.”
Growl.
“Oh, hush.”
The pair made their way to the Castle Ward of Waterdeep. The high elf took several detours on his way to the Font of Knowledge, partly because he was in no mood to have guards eyeing – or questioning – him in this state, and partly because he was dreading the inevitable meeting.

“Hail, good traveler.” The portly lorekeeper greeted Fivin as he approached the steps of the Great Library.
“And hail to you,” the elf waved. “I seek an audience with Mistress Caphaxath of Evermeet University.”
The lorekeeper laughed politely. “I’m sorry, sir, but this is the Font of Knowledge – the Great Library – of Waterdeep. Evermeet University is… well, the name really says-”
“I know full well where Evermeet University is!” Fivin interrupted. “I also happen to know that the Font has access to transpectus mirrors. I therefore repeat my request that I seek an audience with Mistress Caphaxath.”
The keeper’s brow furrowed. “I’m sorry, but our transpectus mirrors are not open to the public. Only a select few academics-”
“And I’m one of them.” Fivin interrupted testily. “Have you read An Investigation into Arcana Natura?”
“Of course!” The lorekeeper said excitedly.
“Well, I was on the subcommittee of colour coordination that approved the binding for Arcana Natura. I was the one that suggested the puce and gold embroidery.”
The man deflated slightly. “Oh, I thought for a second you were going to say you wrote-”
“I know what you thought.” Fivin said. “I didn’t.”
The lorekeeper looked annoyed. “Well, members of colour committees don’t-”
“Colour coordination _sub_committee. There’s a great difference between a main committee and a sub-”
“- don’t count among the select academics. I’m sorry, but the transpectus mirrors are off limits.” The lorekeeper was not going to let himself get interrupted again.
“What if I give you a signed copy of one of my own works?”
The lorekeeper eyed Fivin’s jerkin. During one of the detours enroute the elf had stopped at a fountain and attempted to wipe off the stain. He had only succeeded in making it appear larger and crustier. “What have you written?”
Fivin curtly shrugged at the lorekeeper. “Name a field of study.”
The keeper scoffed. “Engineering.”
Fivin clicked his tongue impatiently. “I am walking with a construct I put together in under an hour from simple household scrap. Be more specific, lorekeeper! To date I’ve written 87 novels on engineering and had 368 articles published on matters dealing with the subject. In fact, after my fantastically disastrous visit to Undermountain I’m also working on two articles on engineering design related to labyrinth and maze construction.”
“Very well, process engineering.”
Fivin smirked. “Trading Wars: The fundamentals of competitive supply line design. A spiritual successor to my earlier work Trading Down: Minimising ergonomic workspace for maximum output.”
The lorekeeper raised an eyebrow. “Entomology.”
The elf waved his hand. “12 novels. My favourite is probably Sticklers: Understanding the fundamentals of stick and leaf insects which inspired my children’s book Leaf me alone! which has already entered its fifth print.”
“Marine geology?”
Great(est) Guide to Geysers and Sea Sulphur Harvesting for Wholesale_.”
“Oenology?”
“_Well-preserved: A guide to good wine handling and grape jam making
.”
“Meteorolo-”
“Look!” Fivin cut him off. “Would it help at all if I mention Heaven’s Fern?”
The lorekeeper’s eyes widened with disbelief. “Twixt-”
“Twixt heaven and thine eyes is not a choice – the choice is whether I tell my Father to find another heir or just let the throne decay.”
“You’re Master-”
The keeper broke off as Fivin shoved a notebook into the man’s face. Property of Fivin Tarkleby – yes that Fivin Tarkleby.
“Right this way!”

“You’re most gracious,” Fivin said as he straightened the robe offered to him by the clergymen.
“It’s only a pleasure,” the priest said. “Few people know that the Font of Knowledge has a tailoring company as a subsidiary. The Library itself isn’t exactly a profitable enterprise.”
Fivin considered himself in the mirror of the intimate chamber he found himself in. “It’s sad that so few people even acknowledge, let alone appreciate, the magic of economics. They think iconic institutions just exist as a convenience for them to peruse when they feel like it.”
The priest nodded excitedly. “It needs to be staffed! Someone needs to wash the floors at least once a week. The latrines need to be cleaned and disinfected regularly, and funds set aside for annual maintenance. Negotiations, arrangements, hustles! People think these places will magically continue existing at their behest. ‘Arcane arts can take you to the infernal plane, but-’”
“‘-but you are there to make a deal with a devil, not pull rabbits from hats.’” Fivin smiled. “The value of a gold piece, page 135.”
The priest grinned. “That book got me into the administration position I am today. Were it not for my vow of celibacy to Oghma, I would’ve named my firstborn after you, Master Fivin.”
The high elf laughed. “If only my patron were half as appreciative, I would have no reason to worry.” His smile faded the longer he looked at the mirror. “Alright, I’m ready.”
The priest nodded and began his incantation, touching select runes along the mirror’s elaborate frame. The glass itself grew duller and rippled. Fivin no longer saw himself reflected, but instead a female moon elf behind a desk. Her features were as sharp as the tip of a quill, framed by dull silver hair. That hair in turn was held back by a brilliant onyx-coloured circlet holding a single cloudy gem that gave the unnerving impression of a ghostly third eye.
“Mistress Caphaxath.” Fivin bowed. “I survived Undermountain.”
“Master Fivin. You weren’t supposed to be in Undermountain.”
“Now-”
“And you definitely weren’t supposed to negotiate with our banking partners to fund an expedition to Undermountain.”
“Well, I-”
“You apparently set up some kind of financial package which you used to lure henchman to help you reach Halastar.”
“That was-”
“Something called,” Mistress Caphaxath looked at a series of papers on her desk. “Dreaded Travel Contingency ‘in-sewer-ants’?”
“Insurance, Mistress. To be paid to a designated loved one in the case of their demise.”
“Well did any of them meet their demise.”
“All of them, Mistress.”
“Master Fivin!” The moon elf stood up from her desk. “Do you have any idea what kind of-”
“They all violated the seduction-clause!” Fivin said.
“The what?” She frantically poured over the papers Fivin surmised was the insurance contract he had negotiated with Pilwicken Bank.
“If the adventurers were burned to death by fire or acid; crushed; or any of the 36 other methods stipulated in section C of the contract, the onus would be on Evermeet University to doubly compensate Pilwicken Bank for the finances lost in accordance with section B(7) of the contract.”
“Precisely! Our institution would have to pay,” Mistress Caphaxath paged through the document, “two-thousand platinum, five gold, seven silver and two copper per person – twice! And you had six of these lummoxes sign this infernal thing!”
“But, like I said, look at the seduction clause. Section C(12).”
Mistress Caphaxath’s eyes scanned the page. “And you’re sure each of them were seduced by a fiend.”
“I was there. We ran into a succubus and her entourage. She seduced all of us. If Pilkwicken Bank doubts my testimony, they’re welcome to extract the truth by magical means, as stipulated in section E.”
Mistress Caphaxath re-read the page. “Fivin, this means-”
“That Evermeet University is responsible for compensating the designated loved ones, and Pilwicken Bank owes us twice that amount. Good thing Evermeet University has some of the most expensive courses on Faerûn. And a scholarship counts as compensation. We’ll be giving children of destitute families the highest quality education available on the material plane, Pilwicken will bankroll it while paying us a generous contribution on top of it, and they’ll get to write the whole thing off as a donation for tax purposes.”
Mistress Caphaxath sat back down and composed herself. She shook her head, then said quietly, “Fivin, if those henchmen died in any other way…”
“I would most likely also have perished, and the life insurance I signed – at great expense – with Strakeln Financing would have paid to Evermeet to more than compensate for the losses.” Fivin felt the past few days hit him all at once. He sat on the floor in front of the mirror, and the grimy Mynx came to rest beside him.
“I died, Shava. I died down there.”
Fivin relayed the events, occasionally glancing at his notes to remember a name. One was slightly smudged: it looked like Seblina or something to that effect. He explained the intricacies of Halastar’s labyrinth, as well as the portal designs and how they function. He explained how he was rescued after watching his whole entourage killed by a succubus, her infernal companion and a cleric of Tiamat. Finishing with the excruciatingly unlucky failure of his blink spell at the most crucial moment, which allowed the death tyrant Netherskull to land a killing blow.
“I also strongly suspect Halastar made a clone of me. It would function like a trap for my soul if I’m to die again.”
After a brief silence Mistress Caphaxath spoke up again. “There should be ways around it. One mad wizard, no matter how powerful, is no match against all of academia. Now these adventurers you ran into.” The disdain for the word was unmistakable. “This ‘Master Aiden,’ ‘Lockenkey,’ ‘Aiden-Mills’ and Rogan…”
“Absolute agents of discord, yet they seem to have achieved a great deal in their short human lifetimes. Apparently known as the “Heroes of Baldur’s Gate.””
Mistress Caphaxath rolled her eyes. “When is that place not giving someone a hero status? I’ve never seen a city more in distress. Although I have read about them somewhere. I thought there were only two heroes.”
“Ah,” Fivin said. “Must be the halfling arcanist and the human priest then.”
“Not Aiden-Mills? He’s a fighter: all they ever dream of is glory and being well-liked.”
“See, I initially thought that too, but the name Aiden-Mills suggests he’s bound to the halfling. Like a rentboy or something.”
“What worries me more is this Frulam woman, the cleric allied to the succubus,” Mistress Caphaxath answered. “There are far too many reports of Tiamat followers congregating. All the talks of bringing her back. I know Zook was looking into them for the Harpers.”
Fivin had not heard the name of his master uttered in a long time. Zook Tarkleby’s last unfinished job: investigate the Dragon Cult in an effort to stop them. Fivin swallowed.
“Mistress Caphaxath, that is why-”
“You want to see this through, don’t you?”
The high elf nodded.
Mistress Caphaxath stared at the elf and sighed. This was not a university-related request: This was Fivin then-Sylvarath asking Shava Caphaxath, his old university friend, study buddy and confidant, whether she could help him.
“I suppose I could negotiate with the Evermeet University senate that supplying resources for saving the world is a worthy business expense.”
Fivin smiled and got to his feet. “It would mean the world to me, Mistress Caphaxath.”
“And the world means a lot to me, Master Tarkleby. I’ll grant your request for a funded sabbatical as long as you produce satisfactory academic writings during your… adventures.”
“I’ve already had two articles sent to the university just before we spoke. One essay postulating on whether a soul can also be cloned, another on death tyrants.”
“I already know the journals to contact for publishing. I’m sure the titles will have the usual Fivin flair.”
“Of course. With Fivin Tarkleby, that’s-”
“That’s the only thing people can be sure of. Evermeet University yearbook, page 34.” Mistress Caphaxath smiled. “Farewell, friend. And good luck.”

#### Umbran

Staff member
... who has had more published papers on numerous topics than Volo, Van Richten and Mordenkainen combined.

The "published papers" form found in modern academia, to me, doesn't normally fit with the low-ish tech of D&D pseudo- Medieval fantasy. As in, published papers require a publishing industry, and subscriptions to those publications. The first academic journal in our world was published in the mid-17th century.

#### Seramus

##### Hero
More importantly - there's a whole lot of space between "absolutely NO rules" and "can be completely systematized". Shades, nuance, and variations are available to us.
Sure! But the moment you step over that threshold away from absolutely NO rules, you've got stuff that can be analyzed if you have sufficient tools.

#### Umbran

Staff member
Sure! But the moment you step over that threshold away from absolutely NO rules, you've got stuff that can be analyzed if you have sufficient tools.

Yeah, but it requires rather more than "we can analyze this one part of it" to turn a thing into "physics," with any relation to the term as we use it today.

#### Seramus

##### Hero
Retracted for getting saucy.

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#### Umbran

Staff member
But at this point you're just responding to get the last word.

Yeah, please don't pretend to be able to read minds over the internet. I'm responding because I'm a physicist, and found your take on it rather misleading.

#### GMforPowergamers

##### Legend
I have over the years used the ffluf that when magic is around there are no natural laws only natural suggestions.... magic makes physics go sit in the corner and cry

#### Parmandur

##### Book-Friend
The "published papers" form found in modern academia, to me, doesn't normally fit with the low-ish tech of D&D pseudo- Medieval fantasy. As in, published papers require a publishing industry, and subscriptions to those publications. The first academic journal in our world was published in the mid-17th century.
But it does derive from a much older form of writing an authoritative text and disseminating it, which goes waaaaaaay back. Before publishing, the ultimate form of peer review was "is this thing worth making a copy of?" And that worked better than one might think at first.

Pretty different, obviously, but close enough for D&D work, probably.

#### GMforPowergamers

##### Legend
But it does derive from a much older form of writing an authoritative text and disseminating it, which goes waaaaaaay back. Before publishing, the ultimate form of peer review was "is this thing worth making a copy of?" And that worked better than one might think at first.

Pretty different, obviously, but close enough for D&D work, probably.
I also assume wizards have SOMETHING like a peer review

#### AnotherGuy

##### Hero
The "published papers" form found in modern academia, to me, doesn't normally fit with the low-ish tech of D&D pseudo- Medieval fantasy. As in, published papers require a publishing industry, and subscriptions to those publications. The first academic journal in our world was published in the mid-17th century.
Well, I suppose I've allowed some level of modernity to have swept into Faerun with this player's character prose.
I'm not averse to what has now become canon in the setting. The printing press and academies are around. Unbeknownst to him - what helps is that I acquired Arcana of the Ancients some time back and have wanted a way to incorporate it. His character is perfect for this Numenera addition.

#### Horwath

##### Legend
Teleport still breaks it. You can teleport in "less time than you can notice or measure" to a planet in a different solar system. Say from Toril to Oerth. Of course, just because you an break or perhaps bend one law of physics with magic, doesn't mean that you can break or bend all of them. The PHB still says that casters access magical energy through the Weave to create a spell effect, so conservation of energy could apply to all magic.
Teleport provides wormhole so it works.

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