Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The no miracles argument against scientific realism

  1. Apr 20, 2010 #1
    The "no miracles" argument against scientific realism

    Let's assume that our best scientific theories tell us something true about the way the world *really* is, in an ontological sense. And further, for simplicity, let's assume a deterministic interpretation of those theories.

    In this view, the universe as we know it began ~13.7 billion years ago. We'll set aside any questions about what, if anything, preceded the first instant and just draw a line there and call that our "initial state".

    Given the specifics of that initial state, plus the particular causal laws of physics that we have, the universe can only evolve along one path. The state of the universe at this moment is entirely determined by two, and only two, things: its initial state and its casual laws.

    But this means that the development of our scientific theories *about* the universe was also entirely determined by the initial state of the universe and it's causal laws. Our discovery of the true nature of the universe has to have been "baked into" the structure of the universe in its first instant.

    By comparison, how many sets of possible initial states plus causal laws are there that would give rise to conscious entities who develop *false* scientific theories about their universe? It seems to me that this set of "deceptive" universes is likely much larger than the set of "honest" universes.

    What would make universes with honest initial conditions + causal laws more probable than deceptive ones? For every honest universe it would seem possible to have an infinite number of deceptive universes that are the equivalent of "The Matrix" - they give rise to conscious entities who have convincing but incorrect beliefs about how their universe really is. These entities' beliefs are based on perceptions that are only illusions, or simulations (naturally occurring or intelligently designed), or hallucinations, or dreams.

    It seems to me that it would be a bit of a miracle if it turned out that we lived in a universe whose initial state and causal laws were such that they gave rise to conscious entities whose beliefs about their universe were true beliefs.

    Note that a similar argument can also be made if we choose an indeterministic interpretation of our best scientific theories.
  2. jcsd
  3. Apr 20, 2010 #2


    User Avatar
    Gold Member

    Re: The "no miracles" argument against scientific realism

    It's a fun idea, but if what is baked into the initial conditions is a modelling relationship between people and their worlds, then the outcomes of such modelling processes would have to be "realistic and true", insofar as that is what modelling results in.

    So you are presuming not only strong determinism, but also the non-application of a self-consistency principle.

    Is is "logical" that there are worlds in which arise - successfully, by familiar evolutionary processes - creatures who can survive with entirely false world models?

    It would seem obvious that determinism has to pass a non-conflicting, self-consistency, test or otherwise we would be talking about illogical worlds.

    So while for the sake of argument, we could grant strong determinism, it seems a step too far (without some further motivating argument) to grant a lack of necessary self-consistency as a second grounding assumption.
  4. Apr 20, 2010 #3


    User Avatar

    Staff: Mentor

    Re: The "no miracles" argument against scientific realism

    Somewhere, someone today won the lottery. Miracle or biproduct of probability and the anthropic principle?
  5. Apr 21, 2010 #4
    Re: The "no miracles" argument against scientific realism

    First, if you're only dealing with the initial conditions and laws of this universe, you can't make any claims about what is 'likely' in other universes.

    Second, we don't need to go to other universes to find belief systems that don't resemble reality.... we have a seemingly endless number of religions to choose from. Given the infinitesimally small number of entities in this universe who understand and use the scientific method, I'd say, even if stumbling on the scientific method is highly unlikely, it would appear we fall within the parameters quite well. We're extremely unusual entities.
  6. Apr 21, 2010 #5
    Re: The "no miracles" argument against scientific realism

    It seems to me that the OP's argument was meant to imply that the scientific method is not well-founded (if taken together with scientific realism). The argument is very similar to the entropy argument, whereby it turns out to be much more likely that the universe just formed as a random fluctuation from equilibrium and all of our memories etc. are false. For me when I see a seemingly endless array of different beliefs the natural reaction is to question my own - I'm dubious to think that I'm the only exception to the rule.
  7. Apr 21, 2010 #6
    Re: The "no miracles" argument against scientific realism

    So I'm starting with an assumption of strong determinism only because it's the simpler case. IF we reach an agreement on that case, then I will explain how my argument extends to the indeterministic case.

    How do "evolutionary processes" differ from regular physical processes? There is no intrinsic difference, right?

    All processes must reduce to fundamental physical laws governing the behavior of fundamental entities. "Evolution" is not a fundamental physical law. There is no "evolution field". There are no "evolution" particles. So what is this "evolution" you refer to?

    "Evolutionary" is just a descriptive label that we can apply to a certain category of processes that share some set of properties that we humans have picked out as significant.

    Evolution doesn't add anything to this discussion because, ultimately, everything is explained by initial conditions and *fundamental* causal laws. In a determinisitic universe, things can only happen one way. So evolution has no real work to do. It's a description of what *has* happened, not an explanation of *why* it happened.

    To quote Paul Davies, from his paper "The Physics of Downward Causation":

    It's actually not too difficult to conceive of a logical, non-conflicting, self-consistent, deterministic universe which nonetheless has initial conditions and causal laws that lead to the existence of conscious entities whose perceptions tell them nothing about the universe they exist in.

    As an example:

    Given our current knowledge of the universe, it would seem that a computer simulation of a human brain would be conscious in the same way that I am conscious.

    Some kinds of 2-D cellular automata are Turing complete and thus could run such a simulation and also have a cache of data that could be fed into the brain simulation in a way that the simulated brain would interpret as sensory data from a surrounding environment. No simulation of the environment actually needs to be done, just time-indexed lookup tables of equivalent data.

    Going further, it seems possible that a very simple "physical" universe could exist with the bare minimum of furniture (e.g., 1 spatial dimension, 1 time dimension, only 1 type of particle that has 2 states, etc.) necessary to implement such a cellular automaton, and a single causal law that was the equivalent of Stephen Wolfram's Rule 110.

    Given the right initial conditions, this cellular automaton would give rise to a human consciousness whose beliefs about how his physical universe really was would be false. Only his beliefs about his perceptions would be true...e.g. "I believe that I'm having the experience of seeing 3 birds fly overhead" would be a true belief. However, "I believe that three birds flew overhead" would be a false belief...because there really are no birds in that universe (not even simulated ones). Also, since that universe only has 1 spatial dimension, there were be no "overhead" either.

    The birds and the extra two spatial dimensions would only exist in the mind of the simulated brain. They would only exist within his perception, not external and independent of it.

    SO...it seems to me that it is NOT possible to show that all conscious entities in a deterministic universe must have even approximately true beliefs. Unless you can show that the above scenario is impossible, or even unlikely compared to our own universe's initial conditions and causal laws.

    Here's a good XKCD comic that runs along vaguely similar lines:


    Also note that the existence of hallucinations and dreams shows, beyond a doubt, that our conscious observations do not necessarily tell us anything about how the universe actually is.

    But science is based on those conscious observations, therefore science does not necessarily tell us anything about how the universe actually is.

  8. Apr 21, 2010 #7
    Re: The "no miracles" argument against scientific realism

    It's a bi-product of the initial conditions of the universe plus the causal laws of physics.

    If that set of initial conditions plus causal laws is so unlikely as to constitute a miracle, then everything that follows from them is also miraculous. Wouldn't you say?

    Though as has been mentioned, how do you put a probability on something like that?

    My central point is that if we are in a deterministic universe, then for us to have *any* true understanding of this universe, that understanding *must* have already been implicit and inevitable in the universe's first instant.

    Which doesn't seem probable if you were selecting a universe at random from the list of conceivable universes. The most common type of conceivable universe would seem to be lifeless universes. The next most common would seem to be universes that gave rise to "life", but where this life never arrives at any true understanding of the universe that contains it. And LEAST common would be universes that contain life which does achieve some true understanding of the universe that contains it.

    In that vein, here's an interesting quote:

  9. Apr 21, 2010 #8
    Re: The "no miracles" argument against scientific realism

    I'm not so sure the universe just randomly happened however I am even less sure about how it could manage to do that.

    Perhaps it's a mix of both? Some aspects are random while others are set in stone?
  10. Apr 21, 2010 #9
    Re: The "no miracles" argument against scientific realism

    I normally don't speculate on 'other universe' models but I don't think the probability of intelligent life arising on other universities should ever be speculated on...

    Saying that it's more likely for universes to exist which don't support life etc. has no basis in my opinion. I would think that if this universe was created from lets call it 'universe birth factory' that their would most likely be an infinite amount of universes. Why would their be a constraint on the amounts? In which case I don't think that even if your probability theory were true I don't think it would be visible given an infinite amount of universes.
  11. Apr 21, 2010 #10
    Re: The "no miracles" argument against scientific realism

    Also I like to say that in my belief if the universe does have causal laws that they are infact all part of only one rule/law and the fact that we see it as many laws put together is only a part of our ignorance imo.
  12. Apr 22, 2010 #11
    Re: The "no miracles" argument against scientific realism

    I think your use of the word 'understanding' is problematic here. There would be no understanding at the beginning of a universe... even if there is an inevitablity to the result. The universe changes, and our understanding works backwards. You're taking the omniscient point of view, which doesn't exist in this universe, and certainly not at the beginning. That is where the fallacy lies.
    I see no reason to give a lifeless universe more or less probability.
    We only have one example, and a bare minimum of understanding of how that one works.
  13. Apr 22, 2010 #12


    User Avatar
    Gold Member

    Re: The "no miracles" argument against scientific realism

    I wouldn't agree. If your idea of physical law fails to capture the idea of self-consistency in outcomes, then your laws must be incomplete.

    This for example is why we have the second law of thermodynamics. Whatever happens, it must be constrained by the global principle of equilibrium. Evolution is the same - an equilibrium principle. The only things that can survive are those that work best.

    Global constraints are just as real as the local constructive actions of a system - despite the fact that reductionist like to believe that macrostates are merely emergent.

    Yes, I often cite that paper because it makes my point here. Material reductionism is incomplete and so you also need the downwards causation of global constraint.

    I don't buy the line that minds are just computations. But that is beside the point here as you seem to be switching tracks.

    Wasn't your OP that we can imagine physically real worlds that arise deterministically from some compact singularity which encoded a set of initial conditions and causal laws?

    So where does a matrix simulation argument fit into this? How does your physical CA realm develop from an intial state to become populated with both a simulated mind and its organised cache of data?

    We can imagine a real world of spatial dimensions, furnished by energetic particles (atoms in a void) deterministically self-organising into something. But there is no explanation for how a CA could just arise and become organised.

    This seems like jumping to yet another argument. If for your simulated mind, its experiences are "true" in the same way our experiences are "true" - that is they are functional in whatever world we may inhabit - then where is the "untruth"?

    We believe we live in a world of solid objects, yet physics can model them as disturbances in fields. Or arrays of point-like particles. Or states in superposition.

    The reality is that we have a variety of models of the world - and they are indeed all models. This does not make any of them false.

    Your argument hinges on some more radical form of false belief - one that is dysfunctional. You are suggesting it would be possible both to have a sincere belief about reality and for it to be entirely wrong, yet still function successfully in that world. The CA argument does not illustrate such a situation.

    But again it is the functionality of our mental states that is what is tested over time. Fortunately, when we are in REM dreams, the brainstem shuts us off from actual action in our world. Those with REM parasomnias can in fact find their false world-modelling rather a serious problem. Same with hallucinatory states.

    So what they show beyond a doubt is that faulty world-modelling is an evolutionary handicap that cannot persist. It may occur fleetingly, but in the long run (and you were talking about long run outcomes in your OP) they must get filtered out by the neutral sieve of evolution as Davies elegantly puts it.

    I think the majority would agree that we cannot know the world, we can only model it. But equally, there is no reason to believe that our modelling could in logic be radically dysfunctional in the way your OP demands.
  14. Jul 30, 2010 #13
    Re: The "no miracles" argument against scientific realism

    I think you omit the possibility that the laws change over time. Then there's the nastiness of time itself to ponder.

    If the universe is deterministic. I think so.

    If the universe is deterministic. I think so.

    We, ourselves, have delved into pseudoscience and religion many times throughout history. We continue to.

    Maybe the probability/possibility of intelligent life developing. Of any sentient life at all existing.

    Again, this has happened to us many times throughout history. It continues to happen. I fail to see the strong link you do between pseudoscience and the fabric of the universe and its laws.

    There will almost inevitably be false beliefs in addition to true beliefs. And they will subsist at least for a while. Look at heliocentrism.

    What you should be pondering in stead is whether there is a link (and if there is, what is it) between the initial state of the universe and its physical laws (whether or not they change over time) and the possibility/probability of intelligent life developing to the point of using the scientific process to further its knowledge of the universe.

    If a species discovers the scientific process then it will probably, eventually, climb out of most of its misconceptions about the world.
  15. Jul 30, 2010 #14
    Re: The "no miracles" argument against scientific realism

    Baked into the non-local deterministic structure of the universe.

    And I can only think of one scenario that can meet this criterion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook