Sophie's Room: A Model of The Universe

Let’s start with just a thought experiment that is a tentative model for how one might argue for God’s existence. I hope this discussion can stay focused on the model argument itself, and what might be issues with it, in the hopes of occasioning some really constructive discussions about method and evidence. Enjoy!!

Imagine a girl named Sophie who lives in a room with only an opaque frosted window. She cannot see through this window; the window just lets light into her room at certain times she calls “day”, but not at other times that she calls “night.” In this room, there is a mirror and objects that are variously bright, but there are no other sources of light besides the window. There are no candles, no flashlights, nothing that could be termed a light source. In fact Sophie has never seen a light source at all, as she has never left this room. And yet, she reasons, at least one light source, one object which is bright in itself and not by the light of another, must exist. Here is the argument she formulates:

  1. There exists bright objects that are not bright of themselves, as I can see around my room.
  2. Objects that are bright, but not of themselves, are bright by the light of another.
  3. Either this other bright object is also not bright of itself and is reflecting the light of another, or it is bright of itself.
  4. If it is bright of itself, then I have arrived at what I aimed to show.
  5. If not bright of itself, then again by the light of another, and perhaps that one from yet another. However, no series of reflectors, however long can be bright without a source of light, i.e. an object that is bright in itself.
  6. Therefore there exists an object which is bright of itself, and not by the light of another.”

Do you think Sophie’s argument is a good one? Do you think it is conclusive? What are the premises that you would like her to provide further justifications of ? Be nice to Sophie, she hasn’t left her room before…

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Her reasoning is faulty. How did she get to ‘objects?’

There is light coming through the window. Without further evidence of something, nothing can be said about the source of the light or even if light has a source. (We know light has a source because that is our experience.) The argument is assuming our experience and applying it illogically to Sophie’s experience. This is fallacious reasoning.

She observes light reflecting off of items. This is a red herring and completely irrelevant. The light shining off the items only occurs when the room is bathed in light. Inferring what occurs in the room to what is occurring outside the room is fallacious. Further, any light outside the room, reflection or not (were she to make a correct analogy) reflection would occur in an environment bathed in light. Reflection only occurs when light comes through the window or is created by the window (We did not rule out the window itself as a light source.)

  1. You never got to an object. You can’t get there from light coming through a window. There is no evidence for the claim of anything outside the window, not even light. All you can say is light seems to come through the window. How could she possibly know something generates light from the light the idea that light simply exists and is its own source? Any reasoning about anything beyond the window, at this point, is fallacious. (How did she rule out the window as the light source?) It seems logical that she would recognize the window as a light-giving

god and worship it. How did she figure out there is light coming through the window? There is light, it comes through the window, it illuminates something more brightly than others. Some items reflect the light in this room. (The End.)

  1. There is no way to get to number 4. The person in the room has never seen anything bright of itself and has no reason to jump to a claim that something could be bright of itself. Perhaps it is the window itself that is bright. She might take a piece of it, hide it under her bed, and see if it glows with the other piece that is on the wall. But then again, it just might not work properly when removed from the other piece. Hmmmm What to do? You can not get there from here.

  2. Self and other… no justification for the claim.

6 You can’t get there based on the information you have.

You are attributing a whole lot of shit to Sophi that she can’t possibly know.,


Having never left the room and never having observed a light source, she would not reasonably conclude that the light source is “bright in itself” as she would have no experience as to whether multiple sources or reflective/projective forces might apply.
In fact, it seems more likely she would extrapolate from what you described as “bright from the light of another” that what you are calling a light source (the window-she has never observed a light source) was indeed bright from the light of another.
Also, the reasoning required would be absent due to the nature of her experience.
The experiment requires an assumption of too many things not declared in the original premise, and is applying knowledge she could not possess.
Ultimately, any of her conclusions could never be verified given her isolation, and would only serve to pass her lonely hours…:sleepy:


The window is a light source. I stopped reading around here.

P.S.: After skimming the argument, I see the conclusion is that a light source must exist (more or less). I have to say I at least agree with that part of the conclusion. Yeah I know it said something silly about the light of another, I’m ignoring that phrase. It just seems like a trivial conclusion, we were already told a light source existed in the story. Or perhaps: I already assumed that Sophie could see the lit up frosty window. :woman_shrugging:t6:


I am not understanding how this analogy is a model of the universe? Also since we were discussing first cause arguments in another thread I’m not sure why this thread was necessary? In that other thread @TheMetrologist also claimed he has objectively verifiable evidence for a deity that created the universe as well, so even the first cause argument seemed moot to me, but then I’m a middling intellect with a mediocre formal education, so I guess my befuddlement is only to be expected.

It’s a metaphor. (muffling my laughter.)

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I have no education in logic, obviously :slightly_smiling_face:, but I do have a question. Are you saying there has to be a first source of light somewhere along the chain ergo there must first be a god of creation? It seems to me that if you want to compare the necessity of a first light source to the necessity of a god of creation then the real question is who created the light source?, and who created the creator of the light source? and so on.

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How is this an argument for a deity, and which one? Also you still have not objectively demonstrated a deity is even possible?

First some fairly straight forward points of reply:

If the window is itself a source of light (understood as the kind the kind of thing that is bright in itself, and not from the light of another) this in no way changes Sophie’s argument. Please attend to what the argument is trying to show: that there must be a source of light. It does try to show that the source of light is this or that object. Or even that it’s an object outside the window.

Perhaps Sophie could have some knowledge that a window transmits light, from other experience with glass. You could add that to the story. But it really doesn’t make any difference here to Sophie’s argument.

When I wrote this, initially I thought about putting the window in a part of the room that Sophie could not see. But instead, I chose to make the window frosty and opaque.

That’s possible. But which piece of knowledge do you have in mind, such that it would make her argument unsound? Look, maybe she has access to books, and has even read about light sources like candles and lightbulbs and stars. But she hasn’t seen any light source before, and is just reasoning to figure out whether they actually exist.

If you ignore the distinction between bright objects that are not bright of themselves and objects which are bright of itself, you miss the point of the argument. Here this is the distinction that I am making between a light source and a reflector (which might be a relative light source, but only insofar as it transmits, not because it generates light.)

It’s a hypothetical, again then, how is this an argument for a deity, and which one? bearing in mind you still have not objectively demonstrated a deity is even possible?

Sophie’s argument is not an argument for god, but it is like an argument for god that I will want to make. Discussing Sophie’s argument first is useful because it allows us to talk about a whole bunch of methodological points that are best made independently from the difficulties proper to an argument for the existence of a god.

I couldn’t agree more. The window is a source of light, therefore there must be a source of light (the window if nothing else). Seems like question begging, but with the first part being embedded into the story, instead of being a labelled premise. :woman_shrugging:t6:

I think perhaps you have not read my explanations sufficiently carefully.

I hope this further clarifies. It is true that in the explanation of the story I call the window “a light source.” But it not started whether it is bright in itself (a light source in the stricter sense of something that generates its own light) or bright by the light of another (because it merely transmits or reflects.)

All I’m saying is you don’t need step 1 - 5. You can throw those away and the argument still works, because you already assumed it in the story. It is trivially true, the best kind; as it can never be wrong.

You could replace lines 1-5 with : I’m a little teapot, short and stout; and your conclusion would still be true.

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No the argument demonstrates the existence of a light source (strictly, an object that generates its own light), and it does not presuppose it.

Where do you think it is assumed in the premises of the argument that a light source exists?

That is exactly my point, it isn’t in a premise, it is in the body of the story. It is a hidden assumption, with the conclusion being little more than this assumption being rephrased.


Are you able to show how it is a hidden assumption of the argument? At which point In the argument does this assumption come in? Just the conclusion? In this later case you’d have to show why the conclusion doesn’t follow from the antecedent (1-5) and is merely inserted at the end. Which I emphatically deny.

@Kellii, thanks for asking :slight_smile: Let me respond to your question in parts.

No, I have not and will not make that argument exactly. But I will offer an argument for the existence of god(s) that looks an awful lot like Sophie’s argument for the existence of at least one light source.

For Sophie’s argument, all that is concluded is that there must exist something that is bright of itself, without needing another light to shine on it in order to be bright. Since it doesn’t need another light to make it bright, there is no need to go back further, no infinite regress.

Of course, if we wanted to account for the existence of light sources, or of anything else, then we would have a different argument, not Sophie’s. That’s something like what I will do later, and I will reason from the realization that there are many things that don’t have to exist but still are, as @Cognotic says very aptly

From this I will reason to the existence of something that is the sort of thing that necessarily is, and therefore does not need to be be explained or caused. Much as Sophie reasons from objects that aren’t bright of themselves, to the existence of objects that are bright of themselves because they emit their own light.

@Sheldon I wanted to start a fresh conversation with a narrower topic. The other thread outlived it’s use of getting folks’ views out on things a while ago, though of course there were many interesting follow up points.

Here I actually want to make a claim or point and defend it. The sort of argumentation that Sophie is engaged in is sound. Her argument works. Perhaps in the course of the discussion I will be compelled by good objections to make modifications to Sophie’s argument (likely, if folks bring up really good objections). Or perhaps abandon that line of reasoning all together (I don’t expect that, but I have to be open to it).

I would be interested in hearing even a brief general account of what you have in mind by “objectively verifiable evidence.”

You can not get to a source of light from your argument. As far as Sophi knows: ‘There is light and it may or may not come through the window.’ She has no means of getting to a source. Why would she even imagine a source? If the window is not the cause/source, (She might be able to test this.) (But as I previously mentioned, the fact that a bit of window does not glow with the rest of the window could just mean it is broken and not working.) there is no reason light is not a thing existing in itself in Sophi’s world. In the world you have created, light can exist without a cause. You need to demonstrate a cause not think it into existence. All you can say is that there is light. You can’t even say the other side of the window. Sopie’s world stops at the window.


Most first-cause arguments do the same thing. You are arguing from what we know to that which we don’t know. The laws of physics break down at Planck time. You can not assert to know anything beyond the universe you find yourself in. Applying what you know here to the unknown is fallacious reasoning. Sophi can not know what is beyond her window. You can not know what is beyond your universe. Putting a god there is just another God of the gaps fallacy. Putting a light source outside the window is unjustified. Putting anything outside the universe is unjustified.

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