• Metaphysician Undercover
    13.2k
    Just take as accepted, anything not counted as physical is not counted as empirical, and anything not counted as empirical in some way is counted as a priori, and anything not counted as empirical in any way whatsoever is counted as pure a priori. It follows that whatever is there that makes changes in one’s subjective condition merely possible, is pure a priori. But it must be something, and thus is established and justified, a precursory condition.Mww

    That's a very clear explanation.

    The sound a lead ball makes is different than the sound a rubber ball makes, and the sound a ball makes is different than the sound a trash compactor makes. That all these make a sound is determined by the the matter of each, but the matter of these, while affecting the senses with sound, do not carry the information of what form the matter has. It is impossible for us to get “ball” out of the sound an object makes when it hits something solid. Without antecedent experience, you cannot get “telephone” out of some arbitrary ringing/clanking/buzzing sound.Mww

    This points directly to what I said to Janus above. Empirical evidence in itself does not justify a belief, what is required is empirical evidence plus logic.
  • Janus
    16.3k
    You just observe evidence with no inference?Metaphysician Undercover

    Of course evidence is such on account of inference; inductive or abductive inferences are not certain, and hence do not constitute proof. Deductive inferences if valid are certain, so they do constitute proof.
  • Srap Tasmaner
    4.9k
    Deductive inferences if valid are certain, so they do constitute proof.Janus

    You meant “don‘t constitute evidence” right?
  • Janus
    16.3k
    You meant “don‘t constitute evidence” right?Srap Tasmaner

    Right, they don't constitute evidence for anything, if the premises are not certain to be true, but they do constitute proof within the context of the premises or provided the premises are true, although they don't prove anything beyond what the premises do in any case, but merely unpack what might at first not be obvious..
  • Andrew M
    1.6k
    What I have been claiming about the number of coins in a jar is simply that we can know a priori that if they can be counted then there is already a specific number of coins in the jar; we can only know a posteriori what that number is.

    I do not think I have ever had occasion to make a claim to knowledge that so clearly fits the definition of a priori. Whaddya know.
    Srap Tasmaner

    Cool! Yes, I think that crystallizes the discussion.

    Perhaps this also says something about how the word "count" is used. For example, if Bob was randomly adding and removing coins from the jar while Alice was endeavoring to count the coins, would we be willing to say that Alice was actually counting the coins in the jar?

    The way I'm thinking about this is that we have a conceptual scheme for how things work (a priori), but this is continually informed by our experience (a posteriori), such that it is possible for our conceptual scheme to change. As part of that, our mathematics can also change. Not necessarily in the sense of x being wrong and y right, but instead that we find that y is a more natural fit than x in particular situations.

    I'm reminded of Rovelli's paper that argues for the contingency of mathematics:

    If there is a "platonic world" M of mathematical facts, what does M contain precisely? I observe that if M is too large, it is uninteresting, because the value is in the selection, not in the totality; if it is smaller and interesting, it is not independent from us. Both alternatives challenge mathematical platonism. I suggest that the universality of our mathematics may be a prejudice hiding its contingency, and illustrate contingent aspects of classical geometry, arithmetic and linear algebra.Michelangelo's Stone: an Argument against Platonism in Mathematics - Carlo Rovelli

    So to apply this to counterfactual-definiteness, here's a hopefully simple example of what might motivate the questioning of it based on experience (at least for some scenarios).

    Suppose that we have a coin, a measuring device (or just observing is OK) and one or more black boxes. When we measure the coin, it is always heads or tails. When we send the coin through the black box and then measure it, it has the orientation it started with only half the time (and not with any discernable pattern). We put this down to the black box having a randomizing element that sometimes flips the coin, sometimes not. Regardless, there's no need to question counterfactual-definiteness.

    One day, someone decides to link two black boxes together, send a coin through them both, and then measure it. To their surprise, they find that the coin is always measured with the same orientation that it started with.

    As evidenced by their surprise, this is a case of experience potentially bringing their conceptual scheme into question. So the challenge is to come up with a natural explanation for all the above measurements (which may either preserve their conceptual scheme or require a change to it).
  • Andrew M
    1.6k
    What type of knowledge do you assume that a "hypothetical" gives someone?Metaphysician Undercover

    A hypothetical (or thought experiment) shows the consequences of particular premises.

    The ancient Greek deiknymi (δείκνυμι), or thought experiment, "was the most ancient pattern of mathematical proof", and existed before Euclidean mathematics,[6] where the emphasis was on the conceptual, rather than on the experimental part of a thought-experiment.Thought experiment - Wikipedia

    When you assume hypothetically that it is raining, this does not mean that you have knowledge that it is raining.Metaphysician Undercover

    No. But the hypothetical shows the consequences that follow when it is raining. Namely that Alice knows that it is raining when, in addition to it raining, she has a justified belief that it is raining.
  • Metaphysician Undercover
    13.2k
    No. But the hypothetical shows the consequences that follow when it is raining. Namely that Alice knows that it is raining when, in addition to it raining, she has a justified belief that it is raining.Andrew M

    That's not what we were discussing though. The issue was, if it must be raining in order for Alice to know that it is raining (i.e. true in your sense), then knowledge is infallible. How does this example show that knowledge is fallible?
  • Andrew M
    1.6k
    The issue was, if it must be raining in order for Alice to know that it is raining (i.e. true in your sense), then knowledge is infallible. How does this example show that knowledge is fallible?Metaphysician Undercover

    It doesn't. The example shows that human fallibility doesn't preclude Alice from knowing that it is raining.
  • Srap Tasmaner
    4.9k
    Perhaps this also says something about how the word "count" is used.Andrew M

    Of course, and this is what I was trying to show in a roundabout away. It was moderately fun to do, and counterfactuals are interesting, but we don’t need any of that, all we need is this:

    (Card) If and only if there is a one-to-one correspondence between the coins in a jar and the set of natural numbers less than or equal to k, for some natural number k, then the number of coins in the jar is k and there is a definite number of coins in the jar.

    That’s just the definition of cardinality for finite sets plus existential generalization. We don’t need counterfactuals for that, and we don’t need them for this:

    (Count) If and only if a jar contains k coins, then counting the coins in the jar yields the value k.

    This definition of cardinality for finite sets might as well be a description of counting; there’s almost nothing else to say.

    *

    I’ll check out the Rovelli. My path suggested that the necessity of mathematical truth is the tipoff; if you go backwards and collect the sorts of things you can know a priori and that are true across any set of possible worlds, the first things you’d find would be what we’ve been calling mathematics, and the rest would be disciplines that aspire to be like mathematics. That’s why math is special, that’s why math is what you can count on, that’s why problems and theories should be formalized mathematically. (If it’s not math, it’s just stamp collecting.)

    *

    I see how your coins and boxes are analogous to photons and interferometers, but I’m still not getting the point here.

    But! I think I have thought of the perfect example, because it also involves making calculations based on values that you should not be using: the two envelopes problem.

    Refresher: The only right way to do this is to treat the envelopes as X and 2X; you don’t know which one you got, so you stand to gain X or to lose X by switching, and the expected value of switching is 0. But if instead, you call whatever you got Y, and then reason that if it’s the bigger the other is Y/2, and if it’s the smaller then the other is 2Y, then the expected value of switching is Y/4.

    It could be that exactly what’s wrong with this analysis is that it relies on counterfactual definiteness. (Oddly, like the black boxes and the interferometers, there are points in the defense of this analysis that rely on the principle of indifference giving equal chances to events, and then relying on those chances as if they were real values. Among many many other issues.)

    I’m still not sure it hooks up with the sort of counterfactuals I’m used to thinking about.

    Talk of switching in either the X or the Y analysis is counterfactual. Why does one of them work and the other not?
  • Andrew M
    1.6k
    all we need is this:

    (Card) If and only if there is a one-to-one correspondence between the coins in a jar and the set of natural numbers less than or equal to k, for some natural number k, then the number of coins in the jar is k and there is a definite number of coins in the jar.

    That’s just the definition of cardinality for finite sets plus existential generalization. We don’t need counterfactuals for that, and we don’t need them for this:

    (Count) If and only if a jar contains k coins, then counting the coins in the jar yields the value k.

    This definition of cardinality for finite sets might as well be a description of counting; there’s almost nothing else to say.
    Srap Tasmaner

    Looks good to me!

    I see how your coins and boxes are analogous to photons and interferometers, but I’m still not getting the point here.Srap Tasmaner

    Assuming the coin always has a definite heads or tails state, even when not measured, what definite state could it have had when it was between the two black boxes? It seems that the coin couldn't have had a definite state, contrary to assumption. (Which is why it is modeled with a wave function, or a linear combination of definite states, or a sum over histories, etc.)

    But! I think I have thought of the perfect example, because it also involves making calculations based on values that you should not be using: the two envelopes problem.

    Refresher: The only right way to do this is to treat the envelopes as X and 2X; you don’t know which one you got, so you stand to gain X or to lose X by switching, and the expected value of switching is 0. But if instead, you call whatever you got Y, and then reason that if it’s the bigger the other is Y/2, and if it’s the smaller then the other is 2Y, then the expected value of switching is Y/4.

    It could be that exactly what’s wrong with this analysis is that it relies on counterfactual definiteness. (Oddly, like the black boxes and the interferometers, there are points in the defense of this analysis that rely on the principle of indifference giving equal chances to events, and then relying on those chances as if they were real values. Among many many other issues.)
    Srap Tasmaner

    Definitely interesting to think about.

    Talk of switching in either the X or the Y analysis is counterfactual. Why does one of them work and the other not?Srap Tasmaner

    Because the Y analysis solves a subtly different problem. Namely, when you choose an envelope, suppose the unchosen envelope is emptied and then randomly filled with half or twice the amount of your chosen envelope. So you should switch in that case.

    In terms of counterfactual definiteness, in the original scenario the envelopes have a definite and unchanging state throughout the experiment. Whereas the in latter scenario, the state of the envelopes can change, depending on your choice, so in a sense is indefinite. Though, of course, at each point in time the envelopes have a definite state.

    If you didn't know which scenario was in play then you would have to collect data, compare the switching strategies and come up with a model of how the envelopes were filled.
  • Metaphysician Undercover
    13.2k
    The example shows that human fallibility doesn't preclude Alice from knowing that it is raining.Andrew M

    The example cannot serve this purpose, because it premises that we can know up front, infallibly whether or not it is raining. You claim to be disproving what is given. Read what you said:

    You and I know up front because I created the hypotheticals that way. The question is not about what you and I know, which is a given, but about what Alice knows.Andrew M

    See the deception? You claim the argument is about "what Alice knows", but you assert a conclusion about "human fallibility". However, your argument has already excluded human fallibility in its premise, as "a given". (That's why my first response was that you begged the question, becauseI thought you were trying to use the argument to prove the infallibility of knowledge). So when you use the example for the purpose you claim. the argument defeats itself, because contrary to begging the question, you ask the person to premise exactly what you are arguing against.
  • Mww
    4.9k
    Regarding the rejection of the idea of intellectual intuition, would you say that is on account of the impossibility of inter-subjective and cross-sensory corroboration?Janus

    Easy part first....cross-sensory collaboration is a physiological impossibility, and inter-subjective collaboration is impossible within the reference frame of its occurrence. We do inter-subjectively collaborate, which is at that point merely a euphemism for post hoc relative agreement.

    The denial of intellectual intuition I don’t think involves either of those. The objects we know about are external to us, but the knowledge we have is of representations of those external objects, and we are not conscious of the transition from one kind to the other. All we know is that it happens and happens necessarily, that is, it is impossible that it doesn’t happen. If we are not conscious of what happens, we are permitted to speculate about it, legislated by the LNC alone. From that, in the speculative construction of a system.....
    (Overlooking the fact the system under construction in speculation, is concurrently in use for the construction)
    ......when this does this and that does that, it is necessary that this cannot be allowed to do that. When the system for knowing things is constructed, and a part of it is of this type, it is self-defeating to then say that part is of a different type, because it then becomes possible that this can do that in violation of the LNC. The idea of an intellectual intuition is reject-able simply because the system has already been constructed in which intuition is governed by the senses.

    Technically speaking, with respect to Kant, that which is intelligible is that which is presented to understanding of a non-material nature, which simply means presented to understanding by itself, absent sensibility, which makes explicit, absent phenomena. In other words, we can think it, which is exactly what noumenon are, re: objects of the intellect. But intelligible, intellectual, does not necessarily imply conceivable schema, that is, representations, subsumed under the thought, which are necessary in order to for a judgement to be forthcoming regarding such intellectual object. We can judge the concept of noumena, because it is a valid conception, but we have nothing by which to judge a noumenal object, because there is nothing by which it is represented.

    Going back to the development of phenomena, the arrangement of matter into a specific form, in conjunction with object of the intellect in which there is no matter to arrange, it is clear that for a representation to become schema for an intellectual object, requires that which does not consider matter, making the arrangement of it moot. This, then, would be an intellectual type of intuition, the type, in accordance with the method of the constructed theory, we do not have.

    All it amounts to in the end, is that we cannot have an intellectual intuition because if we did, the theory itself is logically self-contradictory and internally inconsistent....the very cause of its own destruction. So saying, intellectual intuition, intellectual representation, and therefore a particular noumenon derivable from that, cannot be considered impossible, insofar as the entire speculative system as it belongs to us could very well be wrong, and furthermore, it cannot be said our type of intelligence is the only intelligence there is, which implies noumena are possible conceptions with their own empirical representations, in some other kind of intelligent being.

    One thing I wish I’d accomplished here.....is that over the years of our communications, I had convinced you, or at least persuaded, to disassociate noumena from the ding an sich. In all honesty, on the other hand, I almost wish you’d have convinced me why you haven’t.
  • Mww
    4.9k
    Empirical evidence in itself does not justify a belief, what is required is empirical evidence plus logic.Metaphysician Undercover

    Absolutely, and shouldn’t be contentious. Empirical evidence is contingent, therefore any empirical belief legislated by it, is also contingent. But each empirical belief, in and of itself, in its own time, is nothing but a logical conclusion regarding relative certainty, determinable only by empirically given premises antecedent to the conclusion but concurrent with the evidence.

    But it’s more than just that. The premises themselves, being of the subject/object propositional construct, must have had their subject/object relation already determined logically. If I believe X about Y, I must have already concluded something under logical conditions about X, such that the relation of it to Y, makes my belief coherent. The premises X and Y must logically relate to each other, or I end up with what’s called “...pitiful dogmatic sophistries”.

    Empirical evidence is what there is presented to me; justification is the manner by which the evidence is treated, belief is one of three possible results of the treatment, the other two being opinion and knowledge.
  • Srap Tasmaner
    4.9k
    Before continuing with this, I want to point out that truth is very much the issue at stake in all of these apparent detours. Our customary way of explaining truth is by distinguishing it from knowledge: someone who guesses correctly how many coins are in a jar has put their finger on the truth, even though they do not know how many coins are in the jar, and even though they cannot know that their guess is correct (else it wouldn’t be a guess).

    We can describe a situation in which someone knows that the guess was correct, just not the person guessing, and so we presume that even if no one knew whether the guess was correct, there would be a “fact of the matter” about the quantity of coins, that some sentences about the quantity of coins would be true and some would be false, even if no one knew that, even if no one ever knew that, even if no one ever could know that.

    There was, I believe, a definite number of living spiders on my porch last night at 11 pm, but no one can ever know what that number was, because they weren’t counted and the opportunity to count them is gone forever. If I simply listed all the numbers between 0 and some implausibly high upper bound like 109, one of those numbers would be right, and all of the others wrong.

    Besides the intuitive plausibility of the distinction between truth and knowledge, there is the Church-Fitch argument, which shows that there must be truths (like the spiders on my porch) that are not only unknown by me, but unknowable by anyone, unless you're willing to say that everything that is the case is known. Which is just to say that there is no comfortable resting place partway between identifying truth with knowledge and not doing so.
  • Srap Tasmaner
    4.9k

    Assuming the coin always has a definite heads or tails state, even when not measured, what definite state could it have had when it was between the two black boxes? It seems that the coin couldn't have had a definite state, contrary to assumption.Andrew M

    Still not getting it, so I'll just ask.

    Is this the claim? If each coin left box 1 with a definite state, then it would enter box 2 with a definite state, and if all of the coins entered box 2 with a definite state, then we should see some coins not in their initial orientation? Since we don't, it must not be true that coins leave box 1 and enter box 2 with a definite state.

    What I don't get is that the behavior of the boxes is defined only for coins entering with a definite state, and as emitting coins only in a definite state. What are the boxes doing if not that? Isn't this a way of saying that the behavior of the boxes is not entirely definite?
  • Janus
    16.3k
    Easy part first....cross-sensory collaboration is a physiological impossibility, and inter-subjective collaboration is impossible within the reference frame of its occurrence. We do inter-subjectively collaborate, which is at that point merely a euphemism for post hoc relative agreement.Mww

    I think I can see your reasoning in the rest of your post not quoted above. If I understand you aright, you are saying that since our very notion of intuition (intuition in the Kantian sense, of course) is constructed from reflection on sensory experience, it would thus be contradictory to attempt to apply the notion of intuiton in a context, pure thought, where it would lose its sense. Something like that?

    Regarding what is quoted above, I was talking about inter-subjective and cross sensory corroboration, not collaboration. So, my idea is that our sensory intuitions can be corroborated by others, and it is on the basis of that corroboration, that we posit the existence of external objects, and are able to distinguish between perceptions of real objects and hallucinations. Cross sensory corroboration also allows us to confirm our sensory intuitions. Say, for example I think I see a tree; I can walk up to it and touch it, put my arms around it, tap it and hear its dull resonance, climb it, cut a limb off and so on, none of which would be possible if the tree were an illusion.

    Neither of these procedures would be possible with so-called intellectual intuitions; they would thus have the same status, epistemologically speaking, as hallucinations. So, to get back to the OP, truth seems to be an essentially inter-subjective idea involving common experience of what is external to us. Even our a priori understandings come only from reflection on, and only have their sense in, our culturally mediated experience of a common world.

    As to the distinction between the ding an sich and the noumenon, I see a distinction in that the ding an sich is the empirical object, which is known only by images and impressions, and thus never wholly, but only in glimpses, so to speak. In that sense I understand the ding an sich to be a kind of formal or logical collective representation. That is we think that the external object, which we know only through sensory contacts, and thus only partially and as it appears to us, must also have its own existence; an existence of which we cannot form any substantive conception. I think it is in this sense of the external object as being, in its own existence, wholly alien to our experience, that we think of noumena.

    So, it's not a matter of my not being convinced by your explanations, but of my failure to understand clearly where your explanation differs from mine, as outlined above. I think you understand Kant much more thoroughly than I do, so there must be something I'm not getting. I also acknowledge that what I outlined above is more my own thoughts than it is an attempt to correctly interpret Kant (a task which, judging from the disagreements among Kant scholars I have encountered in my fairly limited reading, is not so easy).
  • Mww
    4.9k
    Something like that?Janus

    Yep, just like that.

    I was talking about inter-subjective and cross sensory corroboration, not collaboration.Janus

    Oh damn. I never once noticed that, until you just brought it up. What a dumbass.
    (Note to self: make more effort to distance braincase from anal cavity)

    The rest...all good.
  • Janus
    16.3k
    Oh damn. I never once noticed that, until you just brought it up. What a dumbass.
    (Note to self: make more effort to distance braincase from anal cavity)
    Mww

    :lol:

    The rest...all good.Mww

    :cool:
  • Andrew M
    1.6k
    The example shows that human fallibility doesn't preclude Alice from knowing that it is raining.
    — Andrew M

    The example cannot serve this purpose, because it premises that we can know up front, infallibly whether or not it is raining.
    Metaphysician Undercover

    No, not infallibly. One can possibly be mistaken about what the premises of the hypotheticals are. But since they are clearly stated, there's no good reason why anyone should be mistaken.
  • Andrew M
    1.6k
    Before continuing with this, I want to point out that truth is very much the issue at stake in all of these apparent detours.
    ...
    Srap Tasmaner

    :up: I agree with all you said there.

    Is this the claim? If each coin left box 1 with a definite state, then it would enter box 2 with a definite state, and if all of the coins entered box 2 with a definite state, then we should see some coins not in their initial orientation?Srap Tasmaner

    Yes.

    Since we don't, it must not be true that coins leave box 1 and enter box 2 with a definite state.Srap Tasmaner

    Correct (given plausible assumptions, namely locality and no-conspiracy).

    What I don't get is that the behavior of the boxes is defined only for coins entering with a definite state, and as emitting coins only in a definite state.Srap Tasmaner

    Not quite. What is defined is what happens when a coin in an initially definite state goes through one or more black boxes and then is finally measured to be in a definite state.

    What are the boxes doing if not that? Isn't this a way of saying that the behavior of the boxes is not entirely definite?Srap Tasmaner

    Not necessarily. The boxes may operate in a well-defined (definite) way, but are instead able to input and output coins in an indefinite state. But that can't be directly confirmed since a coin is always measured to be in a definite state.
  • Metaphysician Undercover
    13.2k
    No, not infallibly. One can possibly be mistaken about what the premises of the hypotheticals are. But since they are clearly stated, there's no good reason why anyone should be mistaken.Andrew M

    You seem to have lost track of the point (if you ever followed it). The point was that we cannot say whether or not "Alice has knowledge" under your description of "knowledge", unless we infallibly know whether or not it is raining. Otherwise we could find out later that it was not knowledge. A hypothetical doesn't provide us with the required knowledge. Therefore, in your example, we cannot truthfully say "Alice has knowledge", or "not knowledge", in either instance.


    As a result of looking out the window, Alice justifiably believes that it is raining outside. For Alice to know that it is raining outside, her justifiable belief also has to be true. Those are the conditions for knowledge. Let's look at two different scenarios:

    (1) If it is raining outside, then Alice knows that it is raining outside. She knows that even though she didn't exclude the possibility that it was not raining and that Bob was hosing the window. She knows it is raining because her belief is both justifiable and true. Alice has satisfied the conditions for knowledge.

    (2) If it is not raining outside (say, Bob was hosing the window which Alice mistakenly thought was rain), then Alice's belief is false. Thus she doesn't know that it is raining, she only thinks that it is. Alice has not satisfied the conditions for knowledge.
    Andrew M

    See, in neither case can we say "Alice has Knowledge", nor "Alice does not have knowledge", because we do not know whether or not it is raining. Even if you assert "it is raining, therefore Alice has knowledge", your assertion does not make it the case that it is raining.
  • Srap Tasmaner
    4.9k
    The boxes may operate in a well-defined (definite) way, but are instead able to input and output coins in an indefinite state. But that can't be directly confirmed since a coin is always measured to be in a definite state.Andrew M

    So the reliance on counterfactual definiteness is here? That perhaps a coin was emitted in an indefinite state but we can’t observe indefinite states, only definite ones. This is like your grid-world example with the direction of the unobserved arrow.

    So the issue is that in some cases there might be no fact of the matter, no definite state, but if we take a measurement, we’ll always find that there is. And then counterfactual definiteness is specifically the claim that since our measurements always show definite states, then what we measure — or, more specifically, what we intend to measure or consider or imagine measuring, must always be in a definite state because indeed that’s what measuring it would show.
  • Srap Tasmaner
    4.9k
    A hypothetical doesn't provide us with the required knowledge.Metaphysician Undercover

    A hypothetical is a conditional, isn’t it? “Suppose I give you a million dollars” is not me giving you squat.
  • Andrew M
    1.6k
    The point was that we cannot say whether or not "Alice has knowledge" under your description of "knowledge", unless we infallibly know whether or not it is raining.Metaphysician Undercover

    When I point out that a premise of the hypothetical is that it is raining, I'm not claiming that it's actually raining outside, here in the real world.
  • Andrew M
    1.6k
    So the reliance on counterfactual definiteness is here? That perhaps a coin was emitted in an indefinite state but we can’t observe indefinite states, only definite ones. This is like your grid-world example with the direction of the unobserved arrow.Srap Tasmaner

    Yes, exactly.

    So the issue is that in some cases there might be no fact of the matter, no definite state, but if we take a measurement, we’ll always find that there is.Srap Tasmaner

    Yes.

    And then counterfactual definiteness is specifically the claim that since our measurements always show definite states, then what we measure — or, more specifically, what we intend to measure or consider or imagine measuring, must always be in a definite state because indeed that’s what measuring it would show.Srap Tasmaner

    Yes, and this is a reason why some physicists and philosophers are not so happy with the term "measurement" here, because it seems to imply that the coin (or particle) is in a definite state prior to measurement.

    Here's physicist Asher Peres on this:

    In this review we shall adhere to the view that [state] p is only a mathematical expression which encodes information about the potential results of our experimental interventions. The latter are commonly called "measurements" - an unfortunate terminology, which gives the impression that there exists in the real world some unknown property that we are measuring. Even the very existence of particles depends on the context of our experiments.
    ...
    The essential difference between the classical and quantum functions which change instantaneously as the result of measurements is that the classical Liouville function is attached to objective properties that are only imperfectly known. On the other hand, in the quantum case, the probabilities are attached to potential outcomes of mutually incompatible experiments, and these outcomes do not exist “out there” without the actual interventions. Unperformed experiments have no results.
    Quantum Information and Relativity Theory - Peres, Terno
  • Metaphysician Undercover
    13.2k
    When I point out that a premise of the hypothetical is that it is raining, I'm not claiming that it's actually raining outside, here in the real world.Andrew M

    Then your hypothetical does squat, as Srap says, toward justifying your claim. We still cannot ever correctly judge that what Alice has is "knowledge", in the real world, because any such judgements could always turn out to be incorrect. Your example only applies to a hypothetical world, in which it actually is raining. What good is it, if it doesn't apply to the real world?
  • Metaphysician Undercover
    13.2k
    In other words, in the real world, it is possible that Alice could have real knowledge, but it is also possible that it is not knowledge. So we cannot correctly judge Alice as having knowledge because we cannot know the answer to this. Alice may have knowledge, or she may not.
  • Michael
    15.6k
    Then your hypothetical does squat, as Srap says, toward justifying your claim. We still cannot ever correctly judge that what Alice has is "knowledge", in the real world, because any such judgements could always turn out to be incorrect. Your example only applies to a hypothetical world, in which it actually is raining. What good is it, if it doesn't apply to the real world?Metaphysician Undercover

    Your argument seems to be that if we cannot be certain that it is raining then it is not actually raining and that if we cannot be certain that it isn't raining then it is not actually not raining. This doesn't follow and is even a contradiction.

    Sometimes, in the real world, it is actually raining, and sometimes, in the real world, it actually isn't raining, irrespective of our certainty and judgements and justifications.
  • fdrake
    6.6k
    @Andrew M @Srap Tasmaner: we had a discussion about that Rovelli paper a few years ago here.
  • frank
    15.8k
    Sometimes, in the real world, it is actually raining, and sometimes, in the real world, it actually isn't raining, irrespective of our certainty and judgements and justifications.Michael

    This is an assumption. You can invite people to share your assumptions, but you can't really bang them over the head with them. Assumptions have no weight.
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Welcome to The Philosophy Forum!

Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.