• Banno
    24.9k
    Indeterminism, causality and information: Has physics ever been deterministic?

    A more direct account of the possibility of indeterminacy in classical physics.
  • Haglund
    802
    Even if you cooled such a system to near absolute zero, you could only constrain the thermal jitter.

    Just as if you could polish the dome to be near frictionless, you wouldn’t actually make it frictionless.
    apokrisis

    It's an ideal dome.
  • Haglund
    802
    Time is not a thing anywayI like sushi

    You can save time, fight against it, waste it, kill it, or collect it. You can measure it and it flies, while at other times time crawls. Time seems some thing.
  • bert1
    2k
    Isn't it just the convergence between mathematical logic and physical necessity that he's talking about?Wayfarer

    I'm always faintly surprised that when I use a tape measure to measure a gap, divide that figure in two, then cut two bits of wood according to the halved figure, the two bits then fit in the gap. Amazes me every time. Why the hell does reality correspond to maths?
  • apokrisis
    7.3k
    It's an ideal dome.Haglund

    Yep. A mathematical abstraction.

    But again, how does it argue against my point - which was that our notions about logical implication and material cause share a reliance on counterfactual reasoning?
  • Haglund
    802
    One deals with physical reality (space-time), whilst the other cares not a jot for itI like sushi

    Precisely. Logical cause and effect are very different from the physical. Logic contains no physics. It's logical that you fall hard on Earth if you jump off the Moon. It's high.
  • Haglund
    802
    But again, how does it argue against my point - which was that our notions about logical implication and material cause share a reliance on counterfactual reasoning?apokrisis

    You said something about the logical law of the excluded middle. Physical reality not excludes the middle.
  • apokrisis
    7.3k
    Physical reality not excludes the middle.Haglund

    Yeah. I said that. :yawn:
  • frank
    15.8k
    Physical reality not excludes the middle.Haglund

    So you're drawing a line between the way we think and the way the world is.

    Once you've done that, there's the problem of how to put them back together.
  • I like sushi
    4.8k
    What is called ‘logical’ in common parse has only a small connection to logic.

    Time is only a thing for mass.
  • sime
    1.1k
    The modern conception of logic (as represented by categorical quantum linear logic) is interactive and game theoretic (e.g quantum, linear), where the role of logic isn't to determine or even to predict the outcomes of experiments (which amounts to superstition and fortune-telling), but merely to define protocols of scientific investigation and to document the outcomes of such investigations.

    In game-theoretic fashion, the material implication A --> B is weakly interpreted to refer to some process of interaction between an observer and his environment, a process that in general is vaguely understood and unreliable. For example, 'A' might stand for a message that Alice sends to Bob, and 'B' might stand for a response that Alice expects to receive from Bob in return. Understood this way, logical implication represents an expected or intented dialogue between interacting entities, rather than representing epistemic certainty with respect to a supernaturally infallible process. The role of the modern logician is thus akin to the role of a tennis umpire, who adjudicates and documents the conduct of interacting actors, whilst remaining agnostic with respect to the outcome of the game.
  • Haglund
    802


    But logical reasoning doesn't necessarily relates to physical cause and effect. A logical cause doesn’t necessarily have a counter weight in the physical world.
  • Haglund
    802
    Time is only a thing for mass.I like sushi

    Not sure I follow. Only a thing for the mass?
  • Haglund
    802
    So you're drawing a line between the way we think and the way the world isfrank

    If logic excludes the middle, the physical reality might follow this or not. It depends on the physics involved. Logic can shape physical reality in all forms. Physical reality though can't shape logical reality how it wants. It's an asymmetrical relation. They can be glued together by observation. Physical reality has limits. Logic has no limits.
  • I like sushi
    4.8k
    It is basic physics - but hard to get your head around too so ‘basic’ does not mean it isn’t mind blowing!

    Everything with mass ‘feels’ time/change. Things without out mass do not - time does not exist for them.
  • Haglund
    802
    What is called ‘logical’ in common parse has only a small connection to logic.I like sushi

    I assume you mean formal logic, taught to children with the "Johnny buys 3 apples, an orange...", "if 40 children in a room are... ...then how many...?" tasks to solve?
  • frank
    15.8k
    They can be glued together by observation.Haglund

    Although it's dubious to say we observed something that's impossible. We'll tend to continue trying to make observations fit with logic somehow even if it takes decades as with quantum theories.

    Physical reality has limits. Logic has no limits.Haglund

    I think logic is about the limits of thought. We can think this way, but not that.
  • Haglund
    802
    Everything with mass ‘feels’ time/change. Things without out mass do not - time does not exist for them.I like sushi

    Ah, you mean mass! I thought you referred to the mass of people... Yes. Photons don't experience time. They connect stuff instantaneously. Their finite speed causes cause and effect. Without a finite SoL, cause and effect, and hence time, don't exist. A logical cause! :grin:
  • Haglund
    802
    Although it's dubious to say we observed something that's impossible. We'll tend to continue trying to make observations fit with logic somehow even if it takes decades as with quantum theories.frank

    You can observe something that's impossible but these impossibilities can turn out to be hallucinations, like a fata morgana, or they are just new possibilities. Like quantum mechanical phenomena were thought impossibilities from a classical POV. The mechanisms of QM are still disputed though. There even were infinite many worlds hypothesized to explain it's functioning.
  • Mww
    4.8k
    On Kant’s response to Hume. Dogmatic slumbers, and such Prussian colloquialisms.....

    “....The celebrated Locke, for want of due reflection on these points, and because he met with pure conceptions of the understanding in experience, sought also to deduce them from experience, and yet proceeded so inconsequently as to attempt, with their aid, to arrive it cognitions which lie far beyond the limits of all experience. David Hume perceived that, to render this possible, it was necessary that the conceptions should have an a priori origin. But as he could not explain how it was possible that conceptions which are not connected with each other in the understanding must nevertheless be thought as necessarily connected in the object—and it never occurred to him that the understanding itself might, perhaps, by means of these conceptions, be the author of the experience in which its objects were presented to it—he was forced to drive these conceptions from experience, that is, from a subjective necessity arising from repeated association of experiences erroneously considered to be objective—in one word, from habit. But he proceeded with perfect consequence and declared it to be impossible, with such conceptions and the principles arising from them, to overstep the limits of experience. The empirical derivation, however, which both of these philosophers attributed to these conceptions, cannot possibly be reconciled with the fact that we do possess scientific a priori cognitions, namely, those of pure mathematics and general physics. The former of these two celebrated men opened a wide door to extravagance**; the latter gave himself up entirely to scepticism—a natural consequence, after having discovered, as he thought, that the faculty of cognition was not trustworthy.....”
    (CPR, B128, in Meiklejohn 1854)
    **enthusiasm in Kemp Smith 1929
    (My emphasis)

    Simply put, Kant’s predecessors agreed humans understand, but no one considered how it is that humans understand. What it means to understand, how is understanding possible and how it works. Transcendental philosophy is nothing but a speculative, albeit logically consistent, exposition of understanding in general, and from it, the possibility and validity of a priori cognitions.
  • sime
    1.1k
    If the universe is assumed to be causally closed and contain a finitely bounded amount of information, then both determinancy and indeterminacy can be rejected as meaningless concepts on the grounds that neither concept can say anything normative or descriptive about a universe that is considered to be a complete dataset.

    Asking whether or not a finitely bounded universe is deterministic or not is like asking whether J R Tolkien's world of Middle Earth is deterministic or not. The question only makes sense relative to some conception of the transcendental, relative to which the world in question can be regarded as incomplete. In the case of the complete works of Middle Earth, the applicable transcendental concept would be the author J R Tolkien , whom when considered from an external perspective transcedendental to Middle Earth can be said to have determined the events of Middle Earth. But when Tolkien and his books are considered together as a complete joint system, the question is again meaningless.

    This is more or less the same observation that Bertrand Russell made when he commented to the effect that the concept of cause and effect adds nothing to the joint description of the motions of the stars and planets.

    Causality is really a means of talking about experimental interventions, in which the actions of an experimenter, i.e the 'causes', are considered to be 'transcendental interventions' with respect to the experiment he is performing. Causality is therefore a "metalogical" concept rather than a logical concept, when we consider a logical system to be finite number of axioms with finite proof lengths that are self-contained.

    Science therefore doesn't need causality per se, but only the concepts of internal versus external reasoning relative to the theories in question, plus a notion of material implication as provided by relevance logic.
  • frank
    15.8k
    never occurred to him that the understanding itself might, perhaps, by means of these conceptions, be the author of the experience in which its objects were presented toMww

    And that's one way to reunite the boundaries of thought to the boundaries of possibility as long as we recalibrate "reality" to the world as we know it, right?
  • Haglund
    802
    If the universe is assumed to be causally closed and contain a finitely bounded amount of information, then both determinancy and indeterminacy can be rejected as meaningless concepts on the grounds that neither concept can say anything normative or descriptive about a universe that is considered to be a complete dataset.sime

    Not sure I understand. Why shouldn't determinism be meaningless in such a universe? I understand that from the outside of such a universe all the events in that universe can be known. If you are part of it, your being in it prohibits knowing all happenings, that's clear. But while in it you can still say there is determinism. Without actually knowing what's determined.
  • T Clark
    13.9k
    It's arguably one of the many causes. I mean, the thing probably wouldn't have shown up there just then had your finger not pressed that spot just then.noAxioms

    Agreed. That's why I wrote "I can see saying that my finger caused the P to show up." That's intended as a non-committal statement. We've gone back and forth on the forum discussing what constitutes causality. Those are questions I don't intend to get in to here.
  • T Clark
    13.9k
    If I push on the keyboard and a P shows up on the screen, I can see saying that my finger caused the P to show up. But isn't that what you are calling physical causation.
    — T Clark

    Isn't it? Didn't I? It's your intentional action, plus a lot of work by the likes of NoAxioms that has been done in the background, to ensure that it works this way.
    Wayfarer

    We're agreed to call that "physical causation." I'm not sure what logical causation is then, if it's not the syllogism I used previously.
  • Agent Smith
    9.5k
    Have you looked into

    1. The Principle of Plenitude

    2. Modal Realism

    Both, more or less, claim that possibile worlds, all of 'em, are actual. If it could be shown that possible actual, our job is done, si?
  • Josh Alfred
    226
    Assigning mathematical quantity to logic such that A=A would be 1=1, and A-->B would be A = B, shows that there can be quantities to be expressed as qualities and visa versa. In binary code 0=0 & 1=1.

    This mathematically and logically specific quantifying of variables of cause (a) to effect (b), and variables equaling themselves and predicates, is of the world of classical physics and classical logic. .

    The classical world breaks down at the quantum level, where a different set of logical and mathematical laws are deducible or express-able.

    Indeed what causes this distinction, (quantum vs. classic) is a mystery in physics. However, they're both set within them deducible laws of math & logic.

    Individualizing specific causes and effects, is the same as making variables logically necessary. That which is already individualized causation makes logic necessary.

    I really don't know if that inspires a further understanding for anyone. I think I am just on the cusp of learning the nature of this (even with Aristotle/Hume/Kant and modern logic), and have yet to dive off into the deep end -- where abysmal complexity abounds. Perhaps, chaos theory or multiple-world theory, and its logical consequences are in those waters.

    *I'm fascinated by such fringe inquiries. Great discussion, looking forward to more.

    *Grabs life-jacket.
  • Philosophim
    2.6k
    Great post Wayfarer! Lets look at a few things.

    Hume recognized that there are two categories of knowledge: empirical and mathematical/logical. He called the former “Matters of Fact” and the latter “Relations of Ideas.”

    First, I would state Hume was unable to prove this separation. Isn't a matter of fact a deduced relation of ideas? I do not hold to this definition.

    Cause and effect in science is really a constant juxtaposition of events. We observe A followed by B. If this happens uniformly through Custom we infer causation, but we have no reason to justify this

    Here is where I believe Hume made a valid point. The idea of cause and effect is that it will necessarily happen again. I calculate gravity, drop an apple, and record the speed. Then I assume if I drop the apple in the same conditions, it will happen again. Why? Why should it be that the laws of physics will be the same 2 seconds from now?

    This cannot be deduced, only inferred by "habit" as Hume notes. We're used to things working consistently, so we assume they will continue to do so. We assume there are laws that will not change, so we make judgements according to those laws.

    Of course, what Hume forgot to think about was, "What cause do we have to believe things will NOT be consistent in the future?" And it turns out, that's an inference too! I believe what we do is choose the most reasonable inference. Looking at history, the rules of physics have not really changed. If people stop breathing, they stop living. Until people can stop breathing and continue to live, it seems more reasonable to assume that breathing is necessary to live. This is Hume's "habit" explained. We walk around with what we have concluded until we are shown otherwise.

    Science takes the same approach. Science never "proves" anything. What it does is try to disprove something. If after trying to disprove something in every single way we can think of, it still stands, then we have "proven" something. The same applies to causality. You can't disprove the notion of causality, period. They computer example is perfect proof. I would love to see someone come along and prove that you didn't cause the keys to be pressed on your keyboard to type your responses.

    So, I have a deep confusion about why philosophy sees this disconnection between logical necessity and physical causation.Wayfarer

    I think a way to explain this is "abstract logic". 1+1=2. Now we know that 1 represents an identity, and 2 represents the recognition of 2 identities together. But what are those identities? How far spaced apart are they? Its not an object, a location, or a thing with weight. Its simply the concept of identities. Bananas, oranges, people, "things". As a logical necessity, 1 identity added with another make 2 identities. Does that mean we'll be able to add a banana from Honduras to a banana from America by bringing them to the same location? We need cause and effect there.

    Now is cause and effect also logical? Yes. But just like all tigers are cats, not all cats are tigers. Cause and effect is not the entirety of logic, but cause and effect is entirely logical.
  • Haglund
    802
    Indeed what causes this distinction, (quantum vs. classic) is a mystery in physics.Josh Alfred

    Doesn't that depend on the interpretation on QM?
  • Mww
    4.8k
    never occurred to him that the understanding itself might, perhaps, by means of these conceptions, be the author of the experience in which its objects were presented to
    — Mww

    And that's one way to reunite the boundaries of thought to the boundaries of possibility as long as we recalibrate "reality" to the world as we know it, right?
    frank

    Hmmmm...not quite sure. If you’d said, “reunite the boundaries of thought to the boundaries of the world as we know it”, I would have agreed outright, insofar as that’s pretty much what Hume, and his Enlightenment empiricist peers in general, didn’t do. Hume denied both the possibility and the validity of pure a priori conceptions, which are the boundaries of thought, yet granted the empirical certainty of mathematics, which is a reality of the world, an impossibility according to Kant and fellow transcendental idealists, because Hume didn’t first derive the conceptions that can only belong to the faculty of understanding itself, outside and beyond the examples of it in experience.

    The philosophical argument is, one cannot even conceive of the predicates of mathematics or the contents of the world, if the pure conception of “quantity” with respect to the former and “reality” with respect to the latter, didn’t already reside in understanding as a natural condition of the human intellect itself. And THAT, is Hume’s problem: the conception of A cause, or THE cause, is impossible if the human intellect didn’t already possess the pure conception of “causality” as a natural precursor. We would never understand that a thing is possible, if we didn’t already possess “possibility”. And this thesis continues with ten more pure conceptions of the understanding, which are called the categories.

    If I misunderstood what you meant, and went off on a useless tangent....let me know so I can adjust accordingly.
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