• Metaphysician Undercover
    13.1k
    The possible world in which I have slippers on is not the one in which I have slippers off. Whether you like it or not, this is not a contradiction.Banno

    What is contradiction is saying that it is the "very same" person in the distinct possible worlds.

    The modal logic is consistent, as Kripke and others have shown in their considerations of possible world semantics.Banno

    Yes, it's consistent because they violate the law of identity, as I described. The three fundamental laws of logic, identity, non-contradiction, and excluded middle are all tied together. If the law of identity is violated, then contradiction can be taken as being consistent. Consistency is judged relative to the axioms employed. Remove the law of identity and all sorts of strange things become consistent.

    But without the metaphysical baggage you attach. A=A is valid. It is a necessary truth. When you say stuff likeBanno

    The law of identity is not valid. If you think it is, then show the logic which proves it.

    Again, no, since the actual world is a possible world. That's been explained to you before.Banno

    OK, so you deny any form of realism. Each possible world is just as likely to be true as any other because there is no real, or actual world to look at for correspondence. And, when you stated that you did not put your slippers on, you were stating this as a possibility rather than as what you believed was actually the case. I apologize for calling you a liar, you are just an anti-realist and did not state your perspective properly.

    By what principles do you propose that I choose one possible world over another, to believe as the truth? In one possible world you put slippers on, and in the other you did not. There is no actual world, so how do you propose that I decide which of the possibilities to believe as the truth? There is no law of identity, so this person "Banno" put slippers on , and the same person, "Banno" did not put slippers on, both at the same time, and there is no actual or real person with that name. Where do I find a hint of truth here?

    Anyway, I hope it is clear to others that Meta's account is quite at odds with Kripke's,Banno

    There's no doubt about that. I thought I made that clear in my first post on this thread.
  • Banno
    25k
    Yes, it's consistent because they violate the law of identity, as I described.Metaphysician Undercover

    It's consistent yet violates the law of identity?

    Well, if it violates the law of identity, then it is by that very fact not consistent. But we know it is consistent; hence, it cannot violate the law of identity. As noted earlier,
    Quantified Modal Logic—which combines individual quantifiers and modal... is sound and complete with respect to constant domain semantics, in which each possible world has precisely the same set of individuals in its domain. — SEP
    My bolding.

    The law of identity is not valid. If you think it is, then show the logic which proves it.Metaphysician Undercover
    Here's a tree proof:
    https://www.umsu.de/trees/#A=A

    The remainder of that post is... increasingly odd. It shows again the error Kripk point to here:
    It is as if a 'possible world' were like a foreign country, or distant planet way out there. — p.174
    and here, again:
    There is no actual world, so how do you propose that I decide which of the possibilities to believe as the truth?Metaphysician Undercover
    Of course there is an actual world. It's one of the possible worlds.
  • Banno
    25k
    Which returns to I think a major bone of contention in Kripke’s thesis, with respect to classes of statements of knowledge and of metaphysics, where he says, pg 177, “Now I hold that neither class of statements is contained in the other”.Mww

    Then comes:"But, all we need to talk about here is this: Is everything that is necessary knowable a priori or known a priori?" and the comments on Goldberg's conjecture.

    I didn't go in to this in any detail, so I might revisit it.

    Goldbergs conjecture is that every even natural number greater than 2 is the sum of two prime numbers. We do not have a proof of Goldberg's conjecture. But we know by calculation that it is true apparently up to 4×10^(18).

    Since it is a mathematical statement, if it is true, then it is true in any possible world - it is necessarily true.

    Since we do not have a proof, we do not know if the conjecture is true.

    Hence we do not know a priori that the conjecture is true.

    Btu if we did have a proof, then we would know a priori that it was true... we would know it was true independently of our experiences...

    Now we know from Gödel that there are always mathematical truths that are not proven.

    The main point is that it is not trivial that just because such a statement is necessary it can be known a priori.

    Well, that looks right. If there are unproven mathematical truths, they are not known, and hence not known a priori.
    ...even if everything necessary is a priori in some sense, it should not be taken as a trivial matter of definition. It is a substantive philosophical thesis which requires some work.
    Of course, for Gödel the truth of such statements was relatively trivial - they said they were true, being of the rough form "This statement is true but unproven". The Goldberg Conjecture works as an example of a potential Gödel statement that is not quite so obvious - it's what such a statement might look like, intuitively true, true in every actual calculation, and yet unproven to be true. It becomes unclear what it might be to claim it is true a priori.
  • RussellA
    1.8k
    Heat is necessarily the motion of molecules. The sensation of heat is not......
    But this does not undermine the broader case that sometimes if A=A, then ☐A=A.
    Banno

    The law of identity
    I don't disagree that if A = A then A = ☐A. As you say "Hence, it is not that "Kripke seems to want to prove something like the law of identity.........I think he takes it as given." Yes, if heat is heat, then heat is necessarily heat. If the motion of molecules is the motion of molecules, then the motion of molecules is necessarily the motion of molecules. If the Eiffel Tower is the Eiffel Tower, then the Eiffel Tower is necessarily The Eiffel Tower.

    However, the law of identity doesn't show one way or another that heat is necessarily the motion of molecules, rather than heat is the Eiffel Tower, for example.

    Heat, temperature and energy are concepts and don't ontologically exist in the world
    Although heat may be transferred by conduction, convection and radiation, keeping with Kripke's description of heat as the motion of molecules. I accept (for the sake of argument) that moving molecules ontologically exist in the world. Consider a body having moving molecules:

    Temperature is the measure of speed of these molecules, the higher the speed the higher the temperature. However, temperature as a concept, as a measure of speed, cannot exist independently of the moving molecules. It cannot have an ontological existence in the world over and above the moving molecules themselves. If there were no moving molecules, there would be no temperature.

    Energy as a concept is a measure of the number of molecules and their speed. Similarly, as a measure it cannot exist independently of the moving molecules. It cannot have an ontological existence in the world over and above the moving molecules themselves. If there were no moving molecules there would be no energy.

    Heat as a concept is a measure of the transfer of momentum from one molecule to another. If a fast moving molecule hits a slow moving molecule, the fast moving molecule slows down, and heat has said to have been transferred. Heat as a measure of the change in movement cannot exist independently of the change in movement. It cannot have an ontological existence in the world over and above the moving molecules themselves. If there were no moving molecules there would be no heat.

    Heat is a concept
    In Bertrand Russell's terms, the existence of heat is not the first-order of an individual but the second-order of a concept. If I tell someone that the next bus will be arriving in 10 minutes, their knowledge has increased, in that my knowledge has been transferred to them. This does not literally mean that knowledge ontologically exists in the world. Similarly, if someone says that heat has been transferred from one object to another, this does not literally mean that heat ontologically exists in the world. Knowledge and heat as concepts are figures of speech.

    "Heat is necessarily the motion of molecules" cannot literally be true
    As heat is a concept that exists only in the mind and not ontologically in the world, and as moving molecules do ontologically exist in the world, the statement "Heat is necessarily the motion of molecules." cannot literally be true as it is comparing two fundamentally different things, though still valid as a metaphor, however.
  • Metaphysician Undercover
    13.1k
    It's consistent yet violates the law of identity?

    Well, if it violates the law of identity, then it is by that very fact not consistent.
    Banno

    Banno, consistency is a relation between the axioms or premises employed. It does not rely on the law of identity. But consistency is commonly related to non-contradiction. If the law of identity is not one of the axioms employed, then the law of of identity is irrelevant to consistency when consistency is determined strictly by non-contradiction.

    Here's a tree proof:
    https://www.umsu.de/trees/#A=A
    Banno

    Ha ha, very funny. I hope you meant that as a joke.

    Of course there is an actual world. It's one of the possible worlds.Banno

    You don't really believe this do you? What about the error you just pointed to, whereby possible worlds are reckoned to be an actual place? How would you reconcile these two, your claim that the actual world is one of the possible worlds, and your insistences that it is an error to think of a possible world as an actual place you might go to?

    This is where Kripke shows his true colours, as a deceptive sophist. He says it's an error to think about a possible world as if it were an actual place that one could go to, yet it turns out that the only realistic way to interpret "possible worlds" is that one of them is the actual world where we live.
    Kripke is anti-realist, but is trying to distance himself from anti-realism:
    Saul Kripke described modal realism as "totally misguided", "wrong", and "objectionable".[27] Kripke argued that possible worlds were not like distant countries out there to be discovered; rather, we stipulate what is true according to them. — https://en.wikipedia.org/wiki/Modal_realism

    Notice, "we stipulate what is true according to them [the possibilities]." As I said, you are being lead firmly into anti-realism. You do not separate the representation (a logical possibility) from the actual world, as consisting of material objects with an inherent identity (by the law of identity). There is no such separation when you insist that the actual world is one of the possible worlds: https://iep.utm.edu/mod-meta/

    This is the problem with Kripke's work which I pointed to already. If we accept his premises as coherent, we have only two ontological possibilities, Platonic realism, or anti-realism. If the "rigid designator" signifies a real object we have Platonic realism, because the logical possibilities are all ideas, mental fabrications, and we say that the mental fabrication is "real". But if we reject the reality of the mental fabrication, (logical possibility or possible world), then we have nothing independent of the mental fabrication, to call "the real world". The real world is just a mental fabrication, as you state here, "it's one of the possible worlds". This is firmly anti-realist, though sophistic authors will present it as a form of realism, "modal-realism", "model-dependent realism", etc..

    The sophistry lies in the way that the supposed actual world is distinguished from the other possible worlds, in this anti-realist structure. To be consistent, all logical possibilities must be represented in the same way, as possibilities. The rigid designator signifies the same possible subject in each. So when you state a counterfactual such as "I might have put my slippers on. I didn't", you speak deceptively because you imply that one of the logical possibilities has a status which the other does not (what actually occurred). But you have no premise to make that conclusion. Therefore your statement is prejudiced and thereby compromised.

    The issue is a logical dilemma. If one of the possible worlds is supposed to be the actual world, then we need some principles whereby we make that judgement, and decide what to believe as the truth. But if we introduce principles (premises) into this logical system whereby one logical possibility would be distinguished from the others as what is actually the case, that would give this one a status which the others do not have, rendering it as other than an equal possibility.

    That's why we ought to reject Kripke's principles altogether. If every logical possibility is equally possible, as indicated by the definition of "rigid designator", and one of the possibilities is supposed to be the actual world, rather than a representation of the actual world, we have no real principles for judging the truth.
  • Mww
    4.9k
    Then comes:"But, all we need to talk about here is this: Is everything that is necessary knowable a priori or known a priori?"Banno

    …..and in the talking about, is the very containment of epistemological within metaphysical statements he denies.

    Since it is a mathematical statement, if it is true, then it is true in any possible world - it is necessarily true.Banno

    ….which is a metaphysical statement regarding knowledge. From a few instances of a posteriori proofs is developed a principle. For any instance other than from experience, in which the principle is the ground, the proof must hold as it did a posteriori. Otherwise, it is impossible to deduce how the principle could be thought in the first place.

    Since we do not have a proof, we do not know if the conjecture is true. Hence we do not know a priori that the conjecture is true.Banno

    It is already given no proof from experience is possible, in that the iterations of the statement are infinite. We have nothing with which to judge infinite conditions, except the logical validity of the principles by which the iterations stand as proven a posteriori, which is of course, the epitome of knowledge a priori.

    It becomes unclear what it might be to claim it is true a priori.Banno

    We don’t care if the conjecture is true, we can’t ever arrive at its finality anyway; we only care that the principles which ground the conjecture, work together and do not contradict themselves. We know a priori the principles of universality and absolute necessity, from which is given the LNC. From the LNC is given validity of the conjecture, even without the possibility of empirical proof for it.

    What it might be to claim it is true a priori, then, is just to show that if it isn’t, the entire base of human intelligence, re: logic, is junk, insofar as if we cannot use the LNC to validate the conjecture, the use of it to validate anything at all becomes questionable, which is itself a contradiction.
  • Banno
    25k
    However, the law of identity doesn't show one way or another that heat is necessarily the motion of molecules, rather than heat is the Eiffel Tower, for example.RussellA

    Quite right. That's @Metaphysician Undercover's error. But given that a posteriori we know that heat = the movement of molecules, then it's the same in every possible world. Or at least, that seems to be Kripke's argument.
    Heat, temperature and energy are concepts and don't ontologically exist in the worldRussellA
    I don't follow that. I don't see how molecules could exist but not their movement.
    This does not literally mean that knowledge ontologically exists in the world.RussellA
    Sure.
    if someone says that heat has been transferred from one object to another, this does not literally mean that heat ontologically exists in the world.RussellA
    Not so sure. Seems to me it means that the average movement of the molecules of one object has increased. That's a statement about how stuff is.
    "Heat is necessarily the motion of molecules" cannot literally be trueRussellA
    I don't agree.

    What will probably be argued by @Mww is that, if heat is the movement of molecules, then while we learned this, it is an a priori fact deriving from the definition of heat.
  • Banno
    25k
    Banno, consistency is a relation between the axioms or premises employed.Metaphysician Undercover

    No so much. It's just that the sentences under consideration do not imply a contradiction. Your definition would only work for axiomatic systems. This definition works for natural deduction as well.

    How would you reconcile these twoMetaphysician Undercover
    Same problem. Possible worlds are stipulated, not recognised. The actual world is a possible world. The alternative would be to claim that the actual wold is impossible.

    The remainder of your post verges on the paranoiac. I'll leave you to it.
  • Shawn
    13.2k
    I got lost a while ago. I thought the reading group ended with the mind-body problem...
  • Banno
    25k
    Just giving folk a chance to grind their axes.
  • Banno
    25k
    let's see if I have understood you.
    From a few instances of a posteriori proofs is developed a principle. For any instance other than from experience, in which the principle is the ground, the proof must hold as it did a posteriori. Otherwise, it is impossible to deduce how the principle could be thought in the first place.Mww
    So... we know stuff only by induction or by deduction?

    It is already given no proof from experience is possible, in that the iterations of the statement are infinite. We have nothing with which to judge infinite conditions, except the logical validity of the principles by which the iterations stand as proven a posteriori, which is of course, the epitome of knowledge a priori.Mww
    You're saying there are truths that have no proof from experience and none a priori. Yep.

    We don’t care if the conjecture is true, we can’t ever arrive at its finality anyway; we only care that the principles which ground the conjecture, work together and do not contradict themselves. We know a priori the principles of universality and absolute necessity, from which is given the LNC. From the LNC is given validity of the conjecture, even without the possibility of empirical proof for it.Mww
    You're saying it doesn't matter if maths is true, only that it is consistent. Perhaps.

    What it might be to claim it is true a priori, then, is just to show that if it isn’t, the entire base of human intelligence, re: logic, is junk, insofar as if we cannot use the LNC to validate the conjecture, the use of it to validate anything at all becomes questionable, which is itself a contradiction.Mww
    I don't see how this works, nor how it follows from what went before. We know from Gödel that there are mathematical truths without proofs. What's puzzling Kripke is what it might mean to call such truths a priori.
  • Mww
    4.9k
    "Heat is necessarily the motion of molecules" cannot literally be true
    — RussellA
    I don't agree.
    Banno

    Heat is the motion of molecules…..as far as our experience informs us. Any empirical knowledge is contingent, therefore heat is necessarily the motion of molecules cannot be literally true. It is only as true as we know as of this point in our experience. Will it always be the motion of molecules? Probably, but we are still not logically justified in saying it is necessarily so. Hume’s problem of induction, T.H.N., 1.,3.,6., 1739. You know……more of that old stuff.

    What will probably be argued by Mww is that, if heat is the movement of molecules, then while we learned this, it is an a priori fact deriving from the definition of heat.Banno

    Not quite. After we learn this, it resides in experience, such that we can say we know a priori heat is the motion of molecules without immediate testing or experience to prove it. Besides, if I read you right, if it is an a priori fact given from definitions, we wouldn’t need experience to prove it.
    ———-

    we know stuff only by induction or by deduction?Banno

    We know empirical stuff by experience, we know possible empirical stuff, or empirical stuff possibly, by induction; we know a priori stuff only by deduction because there is no need for immediate experience on the one hand, and indeed there may not even be any on the other, for that kind.
    ————

    What's puzzling Kripke is what it might mean to call such truths a priori.Banno

    Dunno why it should be puzzling. For that which is true a priori just means there’s no immediate proof from experience, or no proof from experience possible at all. Whatever makes something true in such case, is merely logical.

    Maybe he shouldn’t confuse truth with that which is true. There are no empirical truths; there are only relations between things that do not contradict each other, which makes the relation true under the conditions from which the relation is given.

    I’m not a fan of true/truths as such. Far too ambiguous and subject to the inclinations of whomsoever is professing it. Plus, we gotta keep in mind just what kind of intellect is doing all this knowing and truthing and whatnot.
  • Banno
    25k
    Any empirical knowledge is contingentMww

    Well, see, if you assume this, or take it as a given, then it'll be hard to see why Kripke denies it. His approach is that it is worth reconsidering the relation between necessary/contingent and a prior/a posteriori.

    We do at least agree that this is Kripke's approach, I hope?
  • Mww
    4.9k
    Any empirical knowledge is contingent
    — Mww

    (…) hard to see why Kripke denies it.
    Banno

    Reference? Page number?
  • Banno
    25k
    Well, he gives a variety of examples of what he says are necessary a posteriori facts...

    That Hesperus is Phosphorus, Tully is Cicero, The lectern is not made of ice... things known empirically that he claims are necessary truths.

    No?
  • Metaphysician Undercover
    13.1k
    The actual world is a possible world. The alternative would be to claim that the actual wold is impossible.Banno

    No, the alternative is to understand that the actual world is categorically different from the possible worlds. The former being the material world we live in, the latter being mental constructs. From this alternative perspective, to say that the actual world is a possible world is just a category mistake.

    things known empirically that he claims are necessary truths.Banno

    This is mistaken too. Things known empirically cannot be taken as "necessary truths", because empirical knowledge is fallible.

    As I explained to you, this is why we need the law of identity, to impose necessity on the material world. This law makes a statement about the temporal nature of reality, asserting that what is is necessarily as it is. It makes no claim about specific things known empirically, and its necessity is purely intuitive.
  • Mww
    4.9k
    ….things known empirically that he claims are necessary truths.Banno

    I think this is a misunderstanding…..literally. Things that are known empirically is one thing; that there are necessary truths is quite another.

    It cannot be an absolute necessary truth that H is P, if there was a time when they were known with apodeitic certainty to be different things. The Greeks were quite aware it is absurd to name one thing differently, which makes explicit it was necessarily true for them there were two things, and H was not P. It is only now necessarily true that H/P/V are all one and the same object, which makes the truth of the relation between H and P such that H is P, contingent on the time of its being understood.

    Funny thing about that…..to be consistent with the Greeks, one must have a congruent experience of this particular celestial object, which is merely a bright spot in the sky in the morning and a bright spot in the sky at night, and nothing else whatsoever. Now we arrive at the real necessary truth, and that resides in the quality of whatever experience it is from which the knowledge is given. It never was necessarily true H was P, but it is certainly necessarily true whoever thinks they are, must have the exact same understanding of their experiences. Necessary truth isn’t inferred from what is known, but deduced from the understanding of what may or may not eventually be known.

    If you understand it is necessarily true an object made of wood cannot be made of ice, you must have already understood how an object made of wood manifests as an object of your experience. If you didn’t already understand how a thing is, you couldn’t say how it isn’t. To say a thing known as being made of wood can’t be made of ice, is merely an exercise in cognitive redundancy, which doesn’t tell of anything not already understood. Whether one realizes it or not, is irrelevant; it still happens just like that, with no more or less theoretical speculative authority than Kripke himself posits in his thesis.

    Actually…I take that back. Kripke demeans his speculative authority but asking it repeatedly to be imagined, then informing that to imagine is itself flawed. Why imagine something, only to find out you had no warrant to imagine it? Or that you were doing it all wrong? It surprises me to no end Kripke thinks it even possible to imagine incorrectly, when the very conception of imagination as a human cognitive faculty or capability, precludes it as such, from ever being a source of truth.

    That being said, I don’t want to be told what I shouldn’t do to arrive at something; I want to be told how to get there.

    he gives a variety of examples of what he says are necessary a posteriori facts...Banno

    Yes, he does. But he neglects to mention how, and certainly doesn’t inform as to the possibility that, the examples get to be facts.

    “…. For explanations and examples, and other helps to intelligibility, aid us in the comprehension of parts, but they distract the attention, dissipate the mental power of the reader, and stand in the way of his forming a clear conception of the whole…”
    ————

    Disclaimer: I understand this article is a transcript from an oral lecture. I also understand the audience more than likely has some philosophical background, which means they should have a clue about the subtleties not addressed in the lecture itself.

    As well, being of analytic persuasion, Kripke has no inclination to metanarratives regarding human intelligence. So saying, a proper critique of the article as it stands on its own, confined as it is to language use and intentionality towards it, finds little support for the procedure by which the content of the article comes to be, and non-analytic philosophers will find little agreement with it for that very reason. The best to be said herein, then, is that Kripke is right in his own way but his own way isn’t right.
  • RussellA
    1.8k
    But given that a posteriori we know that heat = the movement of molecules, then it's the same in every possible world. Or at least, that seems to be Kripke's argument...........I don't see how molecules could exist but not their movementBanno

    Justfication three that "heat is the motion of molecules" cannot literally be true.

    Relevant, as Kripke uses "heat is the motion of molecules" as evidence for necessity a posteriori.

    I agree that space and time exist in the world, molecules exist in the world and the movement of molecules exists in the world.

    I still don't agree that heat exists in the world in the same way that molecules and their movements exist in the world. As language transfers knowledge, heat transfers energy.

    Heat
    Heat can be transferred by conduction, convection or radiation. Conduction is a process in which heat is transported between parts of a continuum, through direct physical contact. Convection is the principle, wherein heat is transmitted by currents in a fluid, i.e. liquid or gas. Radiation is the heat transfer mechanism, in which the transition takes place through electromagnetic waves.

    What these have in common is that heat is the process whereby energy is transferred from one body to another. Energy is due to the motion of molecules. Heat is the transfer of energy. Heat is not energy, heat is the transfer of energy. As energy is the motion of molecules, and as heat is not energy, heat is not the motion of molecules.

    Heat is not a substance, it is a process
    Mark Barton, PhD physicist with University of Glasgow, wrote: ""Heat" is a noun and is spoken of as a substance, even in technical language, but it's a misnomer. Strictly heat doesn't exist, it happens: it's the process of energy moving from one system to another via random microscopic interactions."

    1) Heat is the transfer of energy.
    2) Energy is due to the motion of molecules.
    3) Heat is not energy
    4) Therefore, heat is not the motion of molecules.
  • Banno
    25k
    Things that are known empirically is one thing; that there are necessary truths is quite another.Mww
    Well, Kripke isn't going to disagree with that. He says as much. so I don't see how it is a misunderstanding.

    It cannot be an absolute necessary truth that H is P,Mww

    And absolute necessary truth? What's that? I know a necessary truth is true in every possible world. What does absolute do here?

    The Hesperus-Phosphorus example has become overwrought. It's really pretty simple. If, in some possible world, Hesperus is not the very same as Phosphorus, then presumably we have a second, different planet. We would have the planet referred to as Hesperus, and another planet referred to as Phosphorus. This new planet would indeed not be Hesperus, even if it has that name in that possible world. Hence, even though there are possible worlds in which the words "Hesperus" and "Phosphorus" refer to different planets, Hesperus=Phosphorus in every possible world in which they exist.

    Hence, that Hesperus is Phosphorus is an a posteriori fact, discovered by observation and necessarily true.

    The rest of your post seems to be a move from looking at the logic to demeaning the logician.
  • Banno
    25k
    3) Heat is not energyRussellA

    Well, no. Heat is measured in Joules. It is the flow of energy from place to place.

    I don't think we can finesse that away.
  • RussellA
    1.8k
    Well, no. Heat is measured in Joules. It is the flow of energy from place to place. I don't think we can finesse that away.Banno

    I wrote "heat is not energy". The consequence is that Kripke's statement “Heat is the motion of molecules.” is not true.

    1) Heat is the transfer of thermal energy between two bodies, not the flow of thermal energy between two bodies.

    Water when flowing along the Danube can exist independently of either Vienna or Budapest, however, heat cannot exist independently of the two bodies between which it is being transferred.

    2) Are you saying that because heat is measured in joules and energy is measured in joules, then heat is necessarily energy ?

    If so, then it would follow that because the height of the Eiffel Tower is measured in metres, and the height of the Empire States Building is measured in metres, then the Eiffel Tower is necessarily the Empire States Building.

    3) Your argument is that heat, which is the transfer of energy, is energy.

    From https://psiberg.com/thermal-energy-vs-heat
    i) Thermal energy = It is due to the movement of particles in a system
    ii) Heat = It is the transfer of thermal energy

    Then it would follow that:

    The banking system, which is about the transfer of money, is money.
    Language, which is about the transfer of knowledge, is knowledge.
    The football transfer system, which is about the transfer of football players, is the football players.

    All these are true, but only metaphorically.
  • Banno
    25k
    If so, then it would follow that because the height of the Eiffel Tower is measured in metres, and the height of the Empire States Building is measured in metres, then the Eiffel Tower is necessarily the Empire States Building.RussellA

    Gorgeous!
  • Metaphysician Undercover
    13.1k
    1) Heat is the transfer of thermal energy between two bodies, not the flow of thermal energy between two bodies.RussellA

    Even this is problematic because current principles of physics allow that the second body, the receiving body, is not necessary. Radiation of heat from an object is a function of the temperature of the object itself, in relation to absolute zero, such that thermal radiation is not currently understood in terms of a temperature difference between two objects. I believe this principle provides for Kirchhoff's law and "blackbody" physics. Consequently heat can radiate off into nothingness, and from this comes the proposed heat death of the universe.
  • RussellA
    1.8k
    You had me worried for a moment.

    current principles of physics allow that the second body, the receiving body, is not necessaryMetaphysician Undercover

    True, no second body is necessary for thermal radiation, in that the Sun has no "awareness" that the thermal radiation it emits will hit the Earth 8min 20sec later. The thermal radiation could continue into space without ever hitting a second body.

    Radiation of heat from an object........heat can radiateMetaphysician Undercover

    Heat doesn't radiate. Heat is the transfer of thermal energy between two bodies.

    There are three modes of heat transfer, conduction, convection and radiation. The transfer of heat by radiation needs no material carrier. Thermal radiation is electromagnetic radiation.

    It is incorrect to speak of the heat in a body, because heat is restricted to energy being transferred.

    Kirchhoff's law of thermal radiation is regarding a body at temperature T radiating electromagnetic energy. The body is not radiating heat, it is radiating electromagnetic energy.

    The sun doesn't radiate heat, it radiates thermal radiation. If this thermal radiation doesn't hit a second body, as heat is the transfer of thermal energy between two bodies, no heat will be transferred.

    When Theodore Parker said "Cities have always been the fireplaces of civilization, whence light and heat radiated out into the dark", he was using it as a poetic metaphor.
  • Mww
    4.9k
    The rest of your post seems to be a move from looking at the logic to demeaning the logician.Banno

    I’ll own that. I looked at the logic, found it wanting, so tacitly disparage the logician positing the very thing I found wanting. And while I acknowledge my wanting means nothing in The Grand Scheme of Things, it arrives honestly, with due diligence, hence there’s as yet no reason to rethink it.
  • Metaphysician Undercover
    13.1k
    Heat doesn't radiate. Heat is the transfer of thermal energy between two bodies.

    There are three modes of heat transfer, conduction, convection and radiation. The transfer of heat by radiation needs no material carrier. Thermal radiation is electromagnetic radiation.

    It is incorrect to speak of the heat in a body, because heat is restricted to energy being transferred.

    Kirchhoff's law of thermal radiation is regarding a body at temperature T radiating electromagnetic energy. The body is not radiating heat, it is radiating electromagnetic energy.

    The sun doesn't radiate heat, it radiates thermal radiation. If this thermal radiation doesn't hit a second body, as heat is the transfer of thermal energy between two bodies, no heat will be transferred.

    When Theodore Parker said "Cities have always been the fireplaces of civilization, whence light and heat radiated out into the dark", he was using it as a poetic metaphor.
    RussellA

    If I understand you correctly, you say that heat is not in a body, it is the transferal of energy between bodies. However, thermal radiation, which is one mode of heat transferal cannot properly be called "heat", or even "heat energy", because if the thermal radiation does not reach another body there is no heat transferred, i.e. no body being heated. So heat transfers from one body to another, but it's never actually in a body. Nor is it in the radiation which transfer it from one body to another.

    I assume then that "heat" refers to the activity which is the warming or cooling of a body. It is not necessarily a transferal of thermal energy between bodies, because a body can lose heat without another body gaining it. However, the body which loses heat never had heat within it in the first place, you say. "Heat" is really meaningless then, because if it referred to the activity of heating or cooling, it would necessarily be in the body, in order that the body could heat up or cool down. Or is "heat" just metaphor to you?
  • Banno
    25k
    Fair enough. I have something similar in mind, in that there was a logician who revolutionised the formal approach to modal logic, and who applied that formal approach more broadly. And there are a few eccentric posters on a pop forum who disagree with his account because it is at odds with other views they advocate. And while I acknowledge such means little, it arrives honestly, with due diligence, hence there’s as yet no reason to rethink it.
  • Janus
    16.3k
    Well, no. Heat is measured in Joules. It is the flow of energy from place to place.Banno

    In ordinary parlance heating is "the flow of energy from place to place". Something that has been heated becomes hotter (than it was prior to being heated), and is said to possess a (greater) degree of heat. Of course it will cool if it is hotter than the surrounding environment. Cooling is also the the flow of energy from place to place.

    And there are a few eccentric posters on a pop forum who disagree with his account because it is at odds with other views they advocate.Banno

    Ah, the old 'appeal to authority' card has been played.
  • Mww
    4.9k


    Guess that makes us a couple stubborn ol’ peas on either end of an overextended virtual pod, donnit?
  • Banno
    25k
    Guess so.
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