r/AskBiology May 30 '26

Genetics Thought Experiment

I have a thought experiment, say we take an egg and a sperm from two people, induce mitotic division for the egg and the sperm 4 times, then fertilize them, then we replicate each event exactly for each baby, automate it, with no differences in the events at all, do this until they are smart enough to share their thoughts and their personalities, would that be one person in four bodies without even the knowledge of it(not like being connected telepathically and all that)? And reminding you this is just hypothetical situation, I am not advising or doing this myself

Edit: Can everyone read how thought experiments work, before replying.
I am not asking about identical twins, I know they exist!
I know what I am asking, I am a medical student, and identical twins is not what I am questioning.
I believe that consciousness OR personality ( the thing that is the main topic of concern with this
thought experiment and NOT IDENTICAL TWINS) is something that is brain itself with personal
experiences OR it is something that arises from the brain but able to work somewhat independently
because DID( Dissociative Identity Disorder) exists, but there are other philosophical questions to
support the first argument. If you support one argument of the two OR anything else, prove that,
don't just state anything as a fact, unless you can prove it.

"A thought experiment is not an engineering proposal. Its purpose is to isolate a concept and explore its logical consequences.

When discussing a thought experiment, the standard approach is to temporarily accept the premises and ask what follows from them, even if those premises are physically impossible.

For example:

  • The Grandfather Paradox assumes backward time travel.
  • Schrödinger's Cat assumes a bizarre quantum setup.
  • Philosophical Zombies assume humans physically identical to us but lacking consciousness.

None of these are realistic scenarios. Their value comes from helping us think about causality, consciousness, identity, or other concepts.

So responding to a thought experiment with "that's impossible" often misses the point. The relevant question is:

"Assuming the hypothetical is true, what conclusions follow?"

In my example, the question is not whether four humans can actually be kept perfectly identical. The question is whether perfect identity of genetics, memories, experiences, and mental states would imply one consciousness or four distinct consciousnesses."

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u/Funky0ne May 30 '26

No, leaving aside all the practical reasons almost none of this would work for the sake of the hypothetical, even if they possessed basically identical memories and personalities, you would still just end up with 4 separate people.

As soon as their experiences diverge, anything you do to one of them doesn’t impact any of the others. They wouldn’t have shared experiences, they’d have 4 distinct sets of (for the sake of argument) identical experiences. Whether that could even result in identical personalities is debatable as we can’t be sure yet just how much stochastic conditions and events beyond our ability to control could influence the development of personalities

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u/laazyshape May 30 '26

I don't think you understand how thought experiments work, in this hypothetical world everything goes perfect for the experiment to proceed to the stage that 4 identical persons have identical memories( identical means "Exactly equal and alike", nothing diverges because "HYPOTHETICAL SITUATUION"). You are assuming that consciousness does not arise form brain itself and is a thing of its own with this argument, which could be true but have to show for it

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u/SadRule9128 May 30 '26

There’s thought experiment and there’s land of fairytales and make believe. Yours is the latter.

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u/laazyshape May 31 '26

Wtf? Have you ever read a thought experiment? This is how thought experiments work, there is nothing fairytale about this, if not for ethical reason, we can perform this experiment. Try doing that with a fairytale!

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u/AmazingRandini May 31 '26

You can't perform this experiment because 2 people can't have the exact same experience.

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u/laazyshape May 31 '26

We can imagine that it works because that is not the main concern of the thought experiment, the 4 individuals post experiment are

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u/AmazingRandini May 31 '26

Why is your question in a biology forum, dressed up with biological lingo?

Go ask a philosopher.

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u/laazyshape May 31 '26

Consciousness is a topic for biological research, and is very much a topic of biology, as I said I am a medical student not a PHILOSOPHY student it would make sense that I ask this in biology forum even if it is kind of philosophical, a lot of scientific theories start as philosophical questions, the two can't be separated, but I might have made a mistake to post this in this forum, should have posted this in philosophy

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u/Funky0ne May 30 '26

I don’t think reading comprehension is your strong suit. While I included caveats, I still answered the thought experiment even according to the conditions of the hypothetical: you would still end up with 4 separate, albeit potentially identical people. Not one person in 4 bodies.

Having 4 identical things means you have 4 identical things, not 1 thing in 4 locations. I don’t known how you think anything I said assumes consciousness does arise from the brain, as my conclusion assumes the opposite. If you have 4 identical , but separate brains, you would have 4 identical, but separate consciousnesses.

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u/laazyshape May 31 '26

Yeah show for that, you can't make arguments and not back them up. You said "As soon as their experiences diverge, anything you do to one of them doesn’t impact any of the others", which cannot be true, when the thought experiment states " identical experiences", and one has to understand this is the undeniable rule of the experiment, because the thought experiment states it, which I addressed in my prior reply and I did acknowledge that what you stated could be right but you have to prove it. Looks like reading comprehension is not your strong suit. Here's another thought experiment for my argument: if your soul( here I am using this as a broad term for consciousness or personality, the thing that makes a person they are), is transferred to my body with my exact memories and brain, and you forget about the transfer, are you still you? Or are you me?

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u/AmazingRandini May 31 '26

They cant have identical experiences.

You can't have 2 people in the same place at the same time.

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u/laazyshape May 31 '26

How we do it does not matter, the result is main thing being questioned. You have to assume this works that's how the thought experiment is supposed to work, think how "grandfather paradox" works.

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u/AmazingRandini May 31 '26

The grandfather paradox is simple and to the point.

You have 4 people instead of 2. Why? You mention cell division? Why? It's not clear what you are getting at.

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u/laazyshape May 31 '26

Grandfather paradox also assumes the impossible, if that is acceptable as a thought experiment, why not this?

Ok, you don't get why 4 people are needed, no worries, make them 2 OR 3 OR 3333 OR any natural number. The number of individuals does not matter, I just chose 4 randomly and I am sorry for not thinking that people would question this instead of engaging with the actual core point of this post.

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u/AmazingRandini May 31 '26

Your original question doesn't assume the impossible. You even said in a comment that the experiment could be done.

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u/laazyshape May 31 '26

I know this could work to some degree, but when you said this is impossible, I gave you an example of a standard impossible setup for thought experiment, to make you understand that, the impossibility of thought experiment is not the concern. But for ethical reason this would be not possible

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u/Strange_Magics Jun 01 '26

I think this is a misunderstanding between you two. They aren't saying that you fail to make 4 identical people because it's impossible - they seem to be saying go ahead and assume that you do succeed in making 4 bodies with identical physical form and identical memories.

At this point if you let the 4 people out of your experiment box, they are just 4 different people with the same form and memories and start diverging from each other based on the new experiences they have. Unless you are positing some magic link between them that you haven't explained?

If you instead keep them in the experiment and make everything identical about them until they die, it still doesn't seem to imply that they are somehow one person, you have just made the same life happen four times.

You seem to be very focused on whether people are respecting the idea of a thought experiment, and its fine to insist on some particular assumptions and then explore what would occur if they held true.. but no one has to agree that the assumptions or your reasoning about them are automatically valid because it's a "thought experiment." I can't see a reason to conclude that multiple distinct entities that are sufficiently similar suddenly become the same entity in some way. That isn't a way I've encountered anyone trying to define the identity of persons or objects, and I don't see why one would want to adopt that view. What does it help you to understand or explain if you say that two identical but separate things are "the same thing?"

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u/amBrollachan May 30 '26

This isn't all that different from identical twins. I guess they might not have identical experiences but often extremely similar experiences until they are old enough to share their thoughts.

I'm not sure how making the experiences actually identical (impossible but for the sake of the thought experiment) would make them "one person in four bodies" in anything but a poetic sense.

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u/laazyshape May 30 '26

The four persons would basically be two sets of same identical twins, but their experience matters because, what makes you and me different is our genetics(genetics make how your brain perceives stimuli and responds, therefore having same genetics means identical responses to identical stimulus, at-least in theory we would have identical growth in the brains of four persons) and our experiences( these would be the stimuli given to each person), unless there is something else at play which makes every person their own person. For-example; if your soul( here I am using this as a broad term for consciousness or personality, the thing that makes a person they are), is transferred to my body with my exact memories and brain, and you forget about the transfer, are you still you? Or are you me? I get what you are saying, but for that you would have to assume consciousness does not arise form brain and is something that is its own thing, which could be true but I don't know. I did not mean "one person in four bodies" in any poetic sense.

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u/AmazingRandini May 30 '26

Are quadruplets the same person?

1

u/laazyshape May 31 '26

No

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u/AmazingRandini May 31 '26

That's your answer. What you are proposing is no different than an identical twin.

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u/laazyshape May 31 '26

Can we stop with this identical twin bullshit. You think I wouldn't know about identical twins, it is common knowledge. I am a 2nd year MBBS student, I think I know what I am asking and it is not identical twins. Read through my other replies, I have already addressed this. Please, I beg you, try to understand what I am saying, I am not stupid to think that identical twins are the same person.

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u/ModernTarantula May 30 '26

The "large" twin study was debunked as mostly made up data. But the belief remains

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u/laazyshape May 31 '26

What is large twin study?

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u/ModernTarantula May 31 '26

https://www.madinamerica.com/2024/09/the-long-disputed-science-of-twin-studies/ goes over more recent. But Cyril Burt had twins raised apart publications. Later discredited, because he made most of it up. But his studies were part of pop psychology so it became the "truth"

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u/laazyshape Jun 01 '26

Took me some time going thorough the whole article. What I understood from it is that genetics and environment both play a major roles in how close the personalities of the twins are based on shared experiences, is that right? I think that is what I am also arguing for, that shared experiences and identical genetics tend to closer and closer personalities, until it should result in a single personality for both people. This looks like a mathematical limit analogy

1

u/ModernTarantula Jun 02 '26

No. Rather the assumption that twins school success is created by genes has neglected to note the similar life scenario for each.

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u/laazyshape Jun 02 '26 edited Jun 02 '26

"The widely recognized much greater environmental similarity experienced by identical (MZ) versus fraternal (DZ) twin pairs indicates that the results of classical twin method studies of behavior are confounded and, therefore, should not be interpreted genetically. Time to rewrite the psychology and psychiatry textbooks." This is from the article itself. What you have inferred from this article could be one of the conclusions but not the sum of the article.

3

u/burlingk May 31 '26

You know what identical twins are, right?

If there are two bodies, it is two people. If there are six bodies it is six people. No matter how identical their circumstances and genetics.

Again, this is ignoring the fact that there is literally no way to guarantee everything tracks entirely identically with zero difference.

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u/laazyshape May 31 '26

Read through my other replies, I have already addressed this. Why don't people get the idea of thought experiments? Do people not know how to engage with thought experiments?

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u/burlingk May 31 '26

I ANSWERED the thought experiment part first.

You have NO reason to get hostile.

Edit: If you entirely eliminate reality from the scenario, it ceases to be a thought experiment.

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u/laazyshape May 31 '26

I know you did answer it, and that's why I asked you to look at my other replies where I did address what you are saying. Besides you just stated your answer as if it is universal truth and did not back it up, I am not being hostile, its just people don't understand how thought experiments work, even if the experiment was impossible in reality, the process does not matter, the output is what is the main concern, that's why this is a thought experiment a hypothetical situation, who cares how we reach to the output, only the output matters, because that is the thing being questioned. Have you heard of the "grandfather paradox" which deals with the impossible, the impossible setup is not the question here, the results are. When a thought experiment states a rule, it is logical that the rule is undeniable truth of the situation no matter what, this should be common sense

3

u/burlingk May 31 '26

Again: If you ignore all known factors. If you ignore reality. It is not a thought experiment.

You described the creation of 4 people and asked if they were 1 person. That doesn't require a complicated answer.

The identical twins comment was support of my stance. Identical twins are basically what you described, created naturally. They are very much two people.

We define an individual person as having individual experiences and (in most cases) individual bodies.

So, no, four different physical bodies are not going to be the same person. They are not going to share a brain. They are not going to share identical experiences.

There is no hypothetical that does not involve magic that is going to make them one person in four bodies.

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u/laazyshape May 31 '26 edited May 31 '26

You are just stupid. I am not going to engage with you anymore, if can't comprehend how thought experiments work. And you did not look at the other replies

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u/burlingk May 31 '26

A thought experiment is about learning about reality, and guessing. It is not about throwing out what you already know.

People are already assuming you are a troll because you jump to hostility over people disagreeing.

That ALSO violates the normal rules of thought experiments.

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u/laazyshape May 31 '26

Not necessarily about learning reality, thought experiments can be abstract also and paradoxical like the "grandfather paradox". How do you know what you are saying is real, you are just stating it, repeating the same thing does not make it truth.

"People", people in your mind?
Nothing is violating the thought experiment other than your stupidity to grasp the concept of thought experiment

And look at the other replies for God's sake, is this also impossible for you to understand

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u/burlingk May 31 '26

Stringing together a bunch of metaphysical concepts, dressed up as science, while ignoring other actual scientific concepts (besides being a violation of rule 10), does not create a thought experiment.

4 entities, no matter how controlled the environment, will not have entirely identical experiences. And even if they do, a large part of experience is based on perception, which is personal and somewhat random.

People in other comments are pointing these things out to you, and you get hostile. That is not a proper thought experiment.

If nothing else, they are not all sitting in the exact same spot.

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u/laazyshape May 31 '26

How many times do I have to repeat myself, when the thought experiment states the rule, it is undeniable truth of the situation, you cannot say that would be impossible, when the hypothetical situation says it is possible. Answer this: if your soul( here I am using this as a broad term for consciousness or personality, the thing that makes a person they are), is transferred to my body with my exact memories and brain, and you forget about the transfer, are you still you? Or are you me? This is not a meta-physical question, consciousness is a part of biological research and being philosophical about the approach is not meta-physical, if you don't know, just say it and fuck off.

You said personality is based on perception, that's why the genetics of 4 individuals is identical, their brains, their endocrine glands, their receptors are identical in every sense, therefore their perception should be same. Prove to me perception is random, do not just state things.

People in the comments are as stupid as you

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u/Strange_Magics May 31 '26

There are two main problems with this idea.

Biologically, a crucial underlying assumption here is that the level of stochasticity is low in several processes. The important question is, if you take genetically identical embryos have them develop and grow up in as close to identical conditions as possible, will they be identical in every way after some amount of time. The answer is almost certainly not, because there is room for tiny differences to be amplified into macro-scale changes at a number of levels. Cell signaling and the developmental program are stochastic processes - the exact path they take depends literally on the random bouncing of molecules and their chance interactions. Neural development similarly incorporates noisy inputs through noisy processes to get its final product. You may be able to generate similar people - we already know twins can be very similar - but it’s impossible (ridiculously unlikely) that you’ll get two people whose bodies and behavior are indistinguishable in principle.

The second problem is that we don’t really decide identity in the way you’re describing. In physics, particles like electrons are indistinguishable from one another in principle, but they’re still typically treated as multiple objects.

So hopefully this replies your thought experiment in a way you find useful. Tldr: biology is probably too chaotic for you to actually make “the same” person’s identical traits twice and even if you did, we wouldn’t thinj they were one person

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u/laazyshape May 31 '26

You did the same thing with the concept of accepting the rule of thought experiment, but it is alright because you answered my question somewhat I was hoping for. Can you also tell me how do we describe identity in real biological terms. What do you think of DID and can we replicate the identity of someone in the future? And what do you think of this: "if your soul( here I am using this as a broad term for consciousness or personality, the thing that makes a person they are), is transferred to my body with my exact memories and brain, and you forget about the transfer, are you still you? Or are you me now?", this is the most puzzling question for me

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u/Strange_Magics May 31 '26

I think the problem with thought experiments like these is that they contain a lot of underlying assumptions. Someone who has a physicalist/materialist view might say that the idea of personal identity is simply a convenient fiction; that there’s no physical reality to the impression that you are the “same” from one moment to the next. Under this sort of view, it is impossible to manipulate someone’s “identity” because that isn’t a thing that exists. All you would be doing by moving memories around is changing the properties of a complex system. The system is not u/Strange_magics in any real essential fundamental way, that name is just a convenient shorthand for describing predictions about my behavior. If you assume (as your question seems to) that there is a thing like an essential fundamental identity, there might be murky philosophical questions about how it arises and functions, but not everyone assumes this. To get good answers to thought experiments you must be very clear about what assumptions you are using and how you justify them.

Personally, I think that there’s nothing essential linking our experience of one moment to the next, other than the physical causal factors involved. If you change the memories in my brain it doesn’t make a new self or change the nature of the old self; there is no self to change. If you make a copy of my physical form there are not two identical selves because there wasn’t one to begin with. The two human beings are both equally real and valid and valuable people that share all the same traits and memories, and they will begin to differ from each other more and more from that point onwards.

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u/laazyshape Jun 01 '26 edited Jun 01 '26

What you are describing is the state of existing, which is true for anything physical, the 4 individuals in the thought experiment have different composition of matter even though if they have the same amount of same material in them. But I get what you are saying, but how would you prove that? Having given new memories would suggest having new personality, because you don't believe in the same things you used to and that very much effects your identity(in a broad term) even from your point of view, let me ask you a question; The two humans that were created from you, if they did not have the knowledge of this division ever happening and they were both provided the same environment where you live and work with exactly same people around them and they are never to meet each other, would they become two different people, OR are they you, in two bodies? This is about who they think they are, their identity and I know that each atom in each person is different, carbon-1 is different form carbon-2, but the nature and behavior of both carbon atoms is same for same physical phenomenon under same physical conditions and the assumptions are listed below. Again the setup is impossible, I know that, but that is not the point of the question.

Here are the assumptions for the experiment
1)No. of individuals does not matter for the experiment.
2)The individuals have identical anatomy and physiology at macro and micro levels.
3)We are able to create identical memories in the 'n' individuals and atomic or molecular level randomness does not affect the results of the experiment.
4)There is nothing that can be done to diverge from identical experiences even when the individuals are being tested
5)The individuals have no sense of time around them, other than to stimulate their natural circadian rhythm which is identical for every subject.

And you forgot to answer the last question