Why doesn't the Doctor duplicate himself when he has multiple medical emergencies at the same time?

Question

The Doctor in Star Trek: Voyager is a hologram. Voyager's Sick Bay is loaded with holo-projectors.

The episode "Living Witness" shows that the Doctor regularly makes backup copies of himself. After he gets his Mobile Emitter he is able to transfer his program completely to the device.

In a medical emergency with multiple patients, why doesn't the Doctor ever duplicate himself?

If it's a matter of the ship not having enough processing power, why not transfer his program to the Mobile Emitter and then launch his backup copy from the ship's emitters in Sickbay?

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In the episode "Concerning Flight", the ship's main computer core is stolen. This cripples weapons, navigation, transporters, and propulsion yet the Doctor continues on in Sickbay unaware as if nothing has happened.

This suggests that the Doctor requires less processing power to sustain his program than the weapon targeting systems, which makes answers suggesting limited processing power seem less likely to be correct.

Answer 1

In "Basics: Part 1" when Voyager fights multiple Kazon factions, they created multiple holographic fighter ships to distribute the shots from the Kazon ships so that Voyager came under less fire. When they first initialise these holographic ships, the Doctor appears in space stating:

TORRES [OC]: Doctor, are you there? Are you all right?

EMH: I told you we should have run one last systems check.

Indicating that these holographic ships run under the same computer program as the Doctor. This proves that it is, in fact, possible for there to be multiple copies of a hologram running simultaneously. I assume that this never happens in the show for the same reason that transporters cannot create copies, or replicators cannot be used for cloning, yet they can be used to create organs.

There are tons of contradictions like this in the Star Trek series. Stuff like that is inevitable with science fiction, although Star Trek does a very good job at being scientifically accurate as often as possible (where the narrative allows anyways). In one episode of Star Trek (TNG I believe) they used a transporter to get rid of a virus in one of the crew's body using a backup from the transporter logs. If this was truly possible, don't you think they would have done this more often? Such as healing injured crew members, or even bringing them back from the dead?

Answer 2

Despite Living Witness, Voyager does not have enough memory to make a backup copy of the Doctor's program (see the note at the bottom of this Wikipedia article). If he were to create two Doctors using the mobile emitter and Voyager's own memory then both copies would be stuck where they were, since there would be nowhere that either of them could be transferred.

Answer 3

I thought that it was Digital Restriction Management at work. It's probably much more pervasive in Voyager's time than even today and it wouldn't surprise me if even medical units and the military/Starfleet would not be exempt from this.

Answer 4

According to Star Trek technical manuals I've found, and other resources from various places, the Sick Bay systems are completely separate physically from the rest of the ship. It''s got its own power supply, it's got its own replicators, it's even got it's own Emergency Power. It is for all intents and purposes a complete separate system. The only reason the Doctor is at all aware of anything that goes on on the ship is because in Episode 01x02, Janeway has the Doctor's program linked to all logs for everything that happens ship wide. That way he can be made aware of any emergencies that could come up. So therefore the separate system is networked with the rest of the ship.

Also, Sick Bay's systems are mainly only capable of storing one maybe two EMH's at a time. Any other holograms are taken from the main computer's memory, or the holodeck's memory storage. Assuming the doctor needed a secondary back up, he could instruct the computer to transfer a copy of his program into the holodeck, and use It as a secondary Med bay. The only problem with that is that in emergency situations upon all starships, the first systems to be deactivated to reroute power is the Holodeck. Which is done by the computer. This can be seen in TNG Episode 3x06 when the power on the ship is waning and the computer shuts down the holodeck because of it was Standard Operating Procedure.

It must also be taken into consideration that the EMH by his own admission has the sum of almost all the Medical Knowlege known to Starfleet. In order to be able to serve a star ship in the event that something like him would be necessary, and considering the types of encounters most exploration ships have, this would be absolutely necessary.

The size of all of this information would be tremendous, not to mention the computer in Sick Bay most likely draws upon His programmed knowledge when asked a question by the standard medical officer who would normally be there. It would be a waste of space to have both his knowledge, and a copy of this knowledge in the system at the same time.

And since Sick Bay is as stated before a separate system designed to be able to sustain itself in case of a ship wide power failure, or computer failure, we must assume that the amount of space within the computer must be finite.

Answer 5

The Doctors program is "transferred" - cut and pasted - into various places throughout the series, and never copy and pasted. This is, IMO, a mistaken approach, but at least it is consistent. It would suggest that copy an pasting the Doctor would not work, or it would have been done in many situations.

I understand that his memories would not be consistent if he made copies, but they certainly do some re-modelling of his memory on occasions. And I am not sure why missing a few memories is such an issue - one version would have some memories, isn't that enough?

Answer 6

Take your pick:

• Voyager runs on limited resources. The holographic doctor program is supposedly a very big program, very demanding in memory (and presumably processing power too).
• Holograms are usually confined to the holodeck. Having holo-emiters in sickbay was novel technology, might not support more than a single hologram (although this has been contradicted later on. Neelix had holographic lungs for a while in an episode (but even then it was "straining the resources").
• The writers just didn't think that far ahead of the curve.

Answer 7

The question becomes one of ethics.

Let's say the Doctor could duplicate himself to the mobile emitter, and one to the ship. When it becomes time to 'unduplicate' himself, which one do you suppose gets deleted?

If they retain both, the issue is the Doctor's experiences become fragmented. The mobile emitter version would gain knowledge from away missions, and the medical bay version would be contained there forever (also implicitly unethical), but whatever knowledge he gained cannot be shared easily with the one on the away mission, because which parts do you include? Which parts do you cut out? Maybe there were a series of mundane events of minor breakthroughs before he makes one big breakthrough?

This in turn burdens the systems of voyager. It has to maintain two EMHs (which have a history of going wrong), has to leave space for what is essentially duplicate knowledge, and has duplicate processing demands, in what is a power conservation situation where knowledge cannot be consistently shared.

Indeed, the Doctor hasn't been avoiding 'duplicating' himself, he just does it in a different way: he's been training Tom Paris as another medic to help out.

Answer 8

First for context - For some reason this is one thing that was always being changed. At first the doc was so complex they couldn't have a backup or replace him and so it was vital to keep him from being damaged, then they like magic make Crell Maset into nearly as complex of a program, then somehow they manage to make a backup of the doctor only its lost and finally when the doctor is stolen all the sudden they cant make a backup or a new doc let alone a Crell Moset like hologram to be a stopgap.

Second to answer - At least two times more then one hologram was active in sickbay the love interest of the doc and Crell Moset one was an actual humanoid working through the comp. And the other almost as complex as the doc, so it's possible for him to do so but the issue with if he is too complex or not was retconned and retconned so many times it's hard to say anymore.

Answer 9

It is quite common for a program to take up more memory when running than the program takes. As there are two types of memory as most people think of it hard disk space and RAM. Most browsers, for example, would take up maybe a couple of 100mb of disk space but can easily take more than a gig of RAM when running. It's not a perfect example as a browser can have multiple tabs windows open.

As someone who works in IT it seems to me that running a program as complex as the doctor would take up an enormous amount of RAM.

So the doctor's program might take up a relatively small amount of memory (even less if compressed but could be extremely resource intensive while running requiring a large amount of RAM.)

Answer 10

At the beginning of the series, there was a limit in the resources available to the ship. Holograms are complex, the EMH especially so, and having a duplicate was probably too resource intensive when it was just as easy for him to supervise a number of trained assistants.

It wasn't until later on when they found out ways to be able to expand the doctors programming that they could figure out other resources for the buffers.

Answer 11

It is never mentioned, but one problem with running multiple instances is concurrency: maybe Holodoc is not thread-safe. I.e., there are crucial data structures somewhere else that are shared between all EMHs, or something.

Answer 12

A key point not noticed so far: By Voyager's time, computing has long ago evolved into to quantum computing - i.e all major computer hardware exploits features of Quantum Mechanics - superposition, entanglement, etc - to perform computing tasks as effectively as possible (e.g quantum computers can perform searches vastly faster than classical computers because they can use superposition to inspect all search candidates simultaneously). Because of this, computing tasks - such as is needed to generate moving holograms - all run up against a fundamental limitation:

THE NO-CLONING THEOREM: Given a single particle in a specific quantum state, there is no physically possible process that can both leave that particle in its original state and produce a second particle in the exact same state.

The Doctor's hologram is a large assemblage of projected subatomic particles (and not just light, because it is 'solid') which are undoubtedly highly entangled, and so the entire hologram can be viewed as a large particle in a specific, very complicated, quantum state. Projecting a second instance of the Doctor would then require replicating that particle - which is not physically possible.

Answer 13

No other answer seems to mention this, so I'll add it.

Throughout most of the run, the Doctor is treated (as much as possible) the same as any other member of the crew. As critical as he is, he's allowed to continue to expand his program, even though it's been shown to be dangerous (e.g., S03E18, Darkling, where he develops a split personality).

In addition to singing and holophotography, he's allowed to:

• Create a holographic family (S03E22, Real Life)
• Daydream (S06E04, Tinker Tenor Doctor Spy)
• Participate in away missions (note that his holo-emitter is 29th century technology, and as far as we know cannot be replicated, so he risks both that technology and his program in these cases).

He's even granted permission to remain behind on a planet, leaving Voyager without his services (S06E13, Virtuoso), and to travel to the Alpha Quadrant, using a communication link that may not be entirely reliable, risking the permanent loss of his services, to treat his creator (S06E24, Life Line)

We've been reminded, on occasion, that he is a program, such as when the crew of the Equinox removed his ethical subroutines, and he was perfectly happy to experiment on Seven of Nine, even if it would permanently injure her (S05E26 - S06E01, Equinox).

We've also seen that monkeying around with his memories can cause problems (S05E11, Latent Image, where a patient died because of a triaging choice, but he blamed himself and became unable to function). And, the ultimate solution, in that story? Treat him like a biological crewmember, not a program; help him work through the issue until he can get back to work, where he'll probably be an even better doctor for the experience.

So, when he's in the Alpha Quadrant for a month, he's not replaced by a backup. As others have noted, that would leave them in the position of having two programs with unique experiences, and with potential difficulty in merging the programs together again. And, since he has been accepted as a member of the crew, it would be unthinkable to simply delete one copy.

Would a backup copy (assuming they exist, as indicated by "Living Witness") of the Doctor have been used if he had actually left the ship in "Virtuoso"? We simply don't know. He decided not to leave before such an eventuality would have been necessary. I will note that, apparently, he would have taken the one-of-a-kind mobile emitter with him if he left.

TL;DR - The fact that the Doctor is accepted and treated as a member of the crew, not merely a holoprogram, may ethically limit the uses for his program as much as it's limited by the technology on board.

Answer 14

It is my opinion that this would be quite possible to copy the doctor and re-integrate his experiences after running double or even more instances, he is just a program with a database, but it would be too problematic to film the same actor in the same shot repeatedly and because of that they didn't do it.

You have to remember there are hundreds of EMH mark 1 running around scrubbing plasma conduits after the program was replaced by Mk II, many in the same facility. For example, in "Author, Author".

Granted they do not share the same database, but they are running multiple instances of the same program. (i.e the first day the Mk I's were started at the facility they were exactly the same, diverging from that point on).

Answer 15

It is just a story telling device. Since the doctor is a computer program youcan just copy him (hot or cold backup). If the RAM usage (as mentioned earlier) is a concern, you don't need to use RAM for a stored copy, only for a running version.

It is probably theoretically possible to use some sort of synchronisation to keep a sickbay and emitter version of the doctor in sync so that memories and experiences are copied over. Same would be to copy a version of the cooy as a data stream back to the alpha quadrant to treat dr Zimmerman.

The thing is, it makes it all a bit boring. If there is no risk of loss, there is not much of a story. So not being able to copy a holoprogram is imho just a plot device and not a pseudo-technical limitation.

As for copying people using the transporter: i am pretty sure there are moral/ethical reasons to not allow this. On a metaphysical level you could argue that you can copy the body and chemical processes, but not the soul of a person (if you believe in that kind of thing). But again... if you could revert to a backup of yourself as last stored in the teleporter, how boring would that make a scifi series? Bit like "go back to the last save point" in a game :)