Saturday, December 26, 2020

The access problem for mathematical Platonism

Mathematical Platonism takes numbers and other mathematical objects to exist in a third realm distinct from the material and mental worlds, after the fashion of the Forms of Plato’s famous theory.  A common objection to this view, associated with philosophers like Paul Benacerraf, is epistemological.  In order for us to have knowledge of something, say these philosophers, we must be in causal contact with it.  But if numbers are abstract objects outside of space and time, then we cannot be in any such contact with them, because they would be causally inert and inaccessible to perception.  So, if Platonism were true, we couldn’t have knowledge of them.  Yet we do have such knowledge, which (the argument concludes) implies that Platonism is false.  This is known as the “access problem” for mathematical Platonism.

Brown’s defense

Is this a serious problem?  No and yes.  On the one hand, the way the problem is often framed is too underdeveloped and question-begging to worry a sophisticated Platonist.  The idea seems to be that, when we know a chair, for example, that is because light travels from the chair to our eyes, resulting in retinal stimulation, which in turn generates neural activity that brings about a conscious perception of the chair.  But nothing like this is possible where Platonic objects are concerned.

But there are several problems with leaving it at that.  First, as James Robert Brown points out, the objection presupposes that we have a clear and uncontroversial account of how neural processes generate conscious perceptual experiences.  But of course, we don’t, which is why there is such a thing as a mind-body problem.  Now, with occasional exceptions (such as Berkeley), philosophers tend not to take the mind-body problem to be a reason to doubt the existence of the material world.  Though there is no agreement about how conscious experiences can be caused by material objects and processes, they don’t take that to be a reason for us to doubt that there really are material objects and processes, that our experiences are in causal contact with them, and that those experiences therefore give us knowledge of them.  But in that case, Brown quite reasonably concludes, such philosophers can hardly take the absence of an account of how we can get in causal contact with abstract mathematical objects to be a reason to doubt that there are such objects.

Brown also suggests (less plausibly, I think) that quantum mechanics gives us reason to doubt that a causal connection with what is known is really a necessary condition for our knowing it.  He has in mind J. S. Bell’s famous nonlocality result.  Consider an EPR scenario in which two photons arrive at different locations, B and C, from a common source A.  When the photons arrive at their destinations, measurements will show that one has the property spin-up and the other the property spin-down, though nothing about what is happening at A could tell us which photon will have which property.  Furthermore, supposing that B and C are outside of each other’s light cones, information about what is happening at one of these locations cannot get to the other.  Nevertheless, if I know, for example, that the photon that arrives at B has the property spin-up, then I can know that the one that arrives at C will have the property spin-down.  But nothing about any causal relation between A on the one hand and B and C on the other, or between B and C, will have told me this.  And that, Brown says, refutes the assumption that a causal connection is necessary for knowledge. 

But this seems to me not quite right.  After all, if the photons had never been emitted from A, they would not have arrived at B and C, and had I not been there to take the measurement at B, I would not have been able to infer from it what was going on at C.  And these are causal facts.  So, the right conclusion to draw from Bell’s result is not that there are no causal connections at all involved in my knowing what I know, but rather that the causal connections are very weird.  This raises many questions, of course, but I don’t see that they need to be addressed in order to make the narrow point that Bell’s result doesn’t provide a compelling way to respond to the access problem.

Plato’s defense

Another problem with the way the access problem is usually framed is that it rather shamelessly begs the question against Plato himself.  After all, it is hardly as if Plato was unaware of the difficulty of modeling our knowledge of Platonic abstract objects on perceptual knowledge of physical objects.  Indeed, Plato himself insists that knowledge of the Forms cannot work that way.  That’s why he thinks that we must have come to know them prior to embodiment in this life, and why he thinks the soul must be unlike perceptual organs in being immaterial.

In short, Plato is well aware that there is an access problem, but thinks he’s solved it.  Contemporary naturalists don’t like the solution, but part of Plato’s point is that the reality of Platonic objects, and of our knowledge of them, give us reason to reject naturalism.  To object to mathematical Platonism on the grounds that it is hard to square with naturalism is simply to assume, without argument, precisely what is at issue.

Plato would also reject the naturalist’s assumption that explanation is at bottom a matter of identifying relations of efficient causation between material objects.  For Plato, the participation relation that he thinks holds between particular things and the Forms provides another mode of explanation, and teleology yet another.  Of course, the Platonist would have to spell out exactly how Plato’s richer account of explanation can be deployed to solve the access problem.  But the point is that, by simply assuming, without argument, a broadly naturalistic metaphysics and epistemology, the usual way of presenting the access problem does not constitute as powerful an objection as is often supposed, because it simply begs the question against Plato.

Aristotle’s critique

But that doesn’t mean that the mathematical Platonist is out of the woods.  We Aristotelians also reject Platonism, for several reasons, and some of these are relevant to the access problem.  In particular, Aristotle too is critical of the idea that an entity like a Platonic Form could be an efficient cause.  In Metaphysics, Book XII, Part 6, he writes:

But if there is something which is capable of moving things or acting on them, but is not actually doing so, there will not necessarily be movement; for that which has a potency need not exercise it.  Nothing, then, is gained even if we suppose eternal substances, as the believers in the Forms do, unless there is to be in them some principle which can cause change; nay, even this is not enough, nor is another substance besides the Forms enough; for if it is not to act, there will be no movement.

Aristotle’s point here is, first, that something can function as an efficient cause only if it both has an active causal power (which is what a “potency” is in this context), and that power is actually exercised on some particular occasion.  For example, I can cause the pen in front of me to move just by touching it, but I cannot cause it to dissolve just by touching it.  For I have an active causal power of the first sort, but not a power of the second sort.  But in addition to my having the first power, I have to exercise it in order for the pen actually to move.  If I don’t decide to touch the pen, it will just sit there motionless, despite my having the power to move it.

Similarly, Aristotle says, in order for a Platonic Form (or a mathematical object conceived of on the model of a Form) to function as an efficient cause, it would have to have the active causal power to do so, and it would have to be actually exercising that power on some particular occasion.  And Aristotle’s implication is that these conditions don’t hold in the case of the Forms.  They don’t function as efficient causes.  But why not?

Well, think about what, from an Aristotelian point of view, is true of me that makes it the case that I can function as an efficient cause of the movement of the pen.  I am part of a larger system of substances with their own causal powers, the exercise of which contributes to triggering the operation of my own.  For example, the phone rings, which leads me to pick it up, which is followed by somebody on the other end of the line telling me something I want to write down, which leads me in turn to exercise my power to pick up the pen.  All of this unfolds in time and involves my being changed in various ways by the substances I interact with, leading me in turn to bring about changes in them.

These circumstances do not hold of the Forms.  The Forms (and mathematical objects conceived of on the model of the Forms) are eternal and unchanging.  So, nothing could happen to them to trigger the operation of their causal powers, if they have any.  Now, you might respond that God, in Aristotelian-Thomistic theology, is eternal and unchanging, yet he is still said to be an efficient cause.  So why couldn’t the same thing be said of the Forms?

But there is a crucial difference.  There is in God something analogous to intellect and will, but that is not true of the Forms, which are impersonal.  The reason this matters is evident from a point Aristotle makes in On Generation and Corruption, Book II, Part 9, where he writes:

Some… thought the nature of ‘the Forms’ was adequate to account for coming-to-be.  Thus Socrates in the Phaedo first blames everybody else for having given no explanation; and then lays it down that ‘some things are Forms, others Participants in the Forms’, and that ‘while a thing is said to “be” in virtue of the Form, it is said to “come-to-be” qua sharing in, to “pass-away” qua “losing,” the ‘Form’.  Hence he thinks that ‘assuming the truth of these theses, the Forms must be causes both of coming-to-be and of passing-away’…

[But] if the Forms are causes, why is their generating activity intermittent instead of perpetual and continuous – since there always are Participants as well as Forms?

The idea, as I read Aristotle here, is this.  Consider, for example, the Form of Triangle.  It never comes into being or passes away, nor does it change in any other respect.  So, if it is functioning as an efficient cause, its effects – particular triangles – should be similarly temporally unbounded.  They should simply always exist, past, present, and future.  But they don’t – they come into being and pass away.  The point even more obviously holds of living things like Tyrannosaurus Rex, which came into existence at some point and have now gone extinct – even though the Platonic Form of Tyrannosaurus Rex, like every other Form, is eternal.

Now, if we were to attribute something like rationality and free choice to the Forms – as we can to God – we could find a way to make sense of how an eternal cause could have a temporally limited effect.  All we need is the idea there is some reason why the cause saw fit to produce an effect that is temporally bounded in just the way it is.  We don’t need to know what the reason is; the mere fact that there could be one is sufficient to make intelligible the possibility of an eternal cause having such an effect.  (Readers familiar with William Lane Craig’s work might recognize this as among the arguments he gives for the claim that the cause of the beginning of the universe must be personal rather than impersonal.)

But we can’t do this with numbers and other Platonic objects, because, again, they are impersonal.  Hence that way of answering Aristotle’s criticism is not open to the Platonist. 

Aristotelianizing Plato

The problem, to sum up, is that if a thing really has active causal powers, then there has to be something that accounts for how those powers get triggered in the ways they do.  Now, we have such accounts in the case of physical substances (in terms of their relations to other physical substances) and in the case of immaterial mental substances (in terms of their rationality and free choice).  But there is no account available in the case of the purported occupants of Plato’s “third realm” – immaterial but impersonal entities. 

Factor in the Scholastic principle agere sequitur esse (“action follows being”) – that the way a thing acts reflects what it is – and we have the ingredients for an argument to the effect that Platonic Forms would have to be causally inert.  For if there is no way in principle that the causal powers of such Forms could ever be exercised, in what sense would they even have such powers in the first place?

Now, the passages from Aristotle I cited do not address the access problem, specifically, but their relevance to it should by now be obvious.  If mathematical objects conceived of on the model of Platonic Forms would have to be causally inert, then they cannot be what causes us to have knowledge of them.  But then, how do we have knowledge of them?  (Notice that it won’t do to posit some third thing – call it X – that has access to the Forms and then in turn imparts knowledge of them to us.  For that just kicks the problem back a stage.  How could X gain knowledge of the Forms if they are causally inert, and thus cannot be what causes X to know about them?)

Notice that the problem does not arise for the Augustinian position that the Forms (and numbers and other mathematical objects) are to be identified with ideas in the divine intellect.  For then it wouldn’t be the Forms per se that directly act on the world, but rather God, who is not causally inert. 

This position, adopted by later Scholastics like Aquinas and thus sometimes labeled “Scholastic realism” (as opposed to Platonic realism and Aristotelian realism) can be interpreted as a kind of Aristotelianizing of Plato.  Plato posits three realms, the material, the mental, and the Platonic third realm.  Aristotle holds that only the first two are real.  Scholastic realism agrees with Aristotle that there is no third mode of being apart from the material realm and the mental realm.  But it agrees with Plato that truths about mathematical objects and other Forms can’t be grounded in truths about material substances or even in truths about finite mental substances.  Hence it takes the infinite, divine mind to be their ultimate ground.

Exactly how our knowledge of these objects works is another question.  Augustine says it is by illumination, but there are problems with that account.  Whatever the right answer, though, it needn’t be saddled with the difficulties facing Platonism.

Related reading:

Review of Craig’s God Over All: Divine Aseity and the Challenge of Platonism

Frege on what mathematics isn’t

Rucker’s Mindscape

David Foster Wallace on abstraction

Augustine on divine illumination

Plato’s affinity argument

Five Proofs of the Existence of God, chapter 3


  1. It is said in De Spiritualibus Creaturis that, “if a box were self-subsistent apart from matter, it would be something that understands its own self, because immunity from matter is the essential character of intellectuality. And in view of this, the box apart from matter would not be different from an intelligible box.” As far as I’m aware, this is indeed the position of the Platonists, and they indeed gave unto the forms of things the name of gods. So is it necessarily the case that the forms are impersonal? Serious question. I’d appreciate help on this one.

    1. That sounds about right to me. The last step is to recognize that the self-subsistent immaterial box(ness) is identical to an idea in the mind of God, so indeed the forms are personal, eternal, living elements of the divine intellect. They're just not independent gods, or independent concepts (which independence indeed would be fundamentally foreign to the nature of concept or mind or intellect as such).

  2. There are three problems with modern mathematics:

    * Gödel's Incompleteness Theorems strongly imply that logic is broken, and no satisfactory answer has been given to justify the continued usage of logic.

    * There's no connection between how we generalize objects and whether we're talking about the intended object anymore. E.g. A line is defined as "an injective function from (0, 1) to R^n" but then you have the space filling curve, which is a line that has no area but "fills up" a square in the plane. Is that evidence that lines can fill squares, or that "an injective function from (0, 1) to R^n" is not a good definition of a line? This problem doesn't exist, afaik, in physics.

    * There is no idea of a "theory of everything" for mathematics, like there is for physics, biology or chemistry. Which means we have no unifying thread connecting all mathematical ideas.

    Any one of the above would be a catastrophe. But all three?

    1. Goedel's Incompleteness Theorems state that all formal logics are limited, and strongly imply that no algorithm can be equivalent to a true rational intellect. We use formal logics, not to discover mathematical proofs, but to communicate them; and their limitations are no impediment to that end.

      And we don't have a "theory of everything" in physics. Indeed, the two most general theories we do have, general relativity and quantum field theory, have proven fiendishly difficult to reconcile. Our failure to find a unifying thread connecting all ideas of physics does not seem to have kept anyone from using the ideas or thinking about them.

    2. Goedel's Incompleteness Theorems state that all formal logics are limited, and strongly imply that no algorithm can be equivalent to a true rational intellect.

      But the Gödel-type theorems are a problem for those of us who affirm true rational intellect, because they say that it is impossible to even represent in English language the intellectual process used to reason about any meaningful statement in number theory. And if semantics are unrepresentable, then how can they be represented in living beings?

      And we don't have a "theory of everything" in physics. Indeed, the two most general theories we do have, general relativity and quantum field theory, have proven fiendishly difficult to reconcile. Our failure to find a unifying thread connecting all ideas of physics does not seem to have kept anyone from using the ideas or thinking about them.

      I carefully worded it to say that physicists have the idea of a ToE, not that they consummated that idea. There's a difference between having an idea and consummating an idea. Meanwhile mathematicians have no idea of a theory of mathematics. In fact, it wasn't until la fin de siècle that mathematics had an idea of the foundations of mathematics (set theory; Bertrand Russell's definition of the concept of the number one).

    3. "they say that it is impossible to even represent in English language the intellectual process"

      Stop there. Goedel's theorems (and the related work of Tarski, Church and Turing) have nothing to say about English or any other natural language, because English is not a formal logic. The very fact that English has a word for truth is enough to show that - Tarski's Theorem states that no formal logic can represent the set of true statements it can express, but English speakers can assert that a statement is true quite easily.

      And if a "unifying idea" for mathematics has to be a project like Bertrand Russell's, to get all of math into one formalized system - then yes, Goedel's work showed that there isn't, and cannot be, any such "unifying idea". But just as not having a single equation that describes all material phenomena is no obstacle to doing physics research, not having a single set of axioms to derive all mathematics from is no obstacle to doing mathematical research.

      Indeed, it's very much in doubt whether the work in "foundations of mathematics" is even a fruitful direction for mathematical research. For instance, the set of finite ordinals in ZF set theory does represent the concept of the natural numbers; but it does not IMO give any more insight into that concept than the Peano axioms do. In practice mathematicians forget the set-theoretic representation of numbers when they work on number theory.

  3. Merry Christmas Dr. Feser! I am curious to ask, how much study of the actual Mathematics or Physics do you undertake when writing your blog posts or your books more generally? Do you take time to learn the Math and Science you are commenting on, or rather cite the work of accredited experts in these fields?

  4. I claim no expertise in this area, so the following questions are asked for reasons of clarification. They are not meant to be critical.

    1. I understand that Godel's Incompleteness Theorum establishes that for any axiom system complex enough to include arithmatic, mathematical truths exist which cannot be established as such in that system. Further axioms may be added however, at which point the situation just reoccurrs at a higher level.

    How does this strongly imply ( or imply at all ) that 'logic is broken'?

    2. As we are free to invent our base axiom system in mathematics, why would be expect there to be a 'theory of everything' in mathematics, indeed how could there be? And what is the problem with that?

    1. Your understanding of Gödel's incompleteness theorems is not entirely correct. Gödel's incompleteness theorems imply that there is no formal logical system that can prove anything nontrivial in number theory. In fact, Gödel-type theorems are a pattern. Here are three Gödel-type theorems:

      1. Adian–Rabin theorem: no formal logical system can prove anything meaningful about groups.
      2. Rice's theorem: no formal logical system can prove anything meaningful about computer programs.
      3. Gödel's incompleteness theorems: no formal logical system can prove anything meaningful about numbers.

      But mathematicians have a method for reasoning about the semantics for groups/algoriths/numbers all the time. These Gödel-type theorems taken literally say that no such thought process can exist! That's a pretty big failure if you ask me! That's an even bigger problem than the cosmological constant problem!

    2. I believe that the eminent Nobel Prize winning physicst and mathematician Roger Penrose has written extensively about this kind of thing , starting with ' The Emperor's New Mind' back in 1989. He is a naturalist though, and thinks that the points you make indicate that the workings of the human cerebral cortex are based on currently unknown physics which transcends general relativity and quantum mechanics. I would be most interested to know what other naturalistic thinkers with real expertise in this area have made of the arguments.

    3. "How does this strongly imply ( or imply at all ) that 'logic is broken'?"

      It doesn't. Gödel's incompleteness theorem(s) is a *theorem* after all, a logical deduction formalizable in some background theory, so if "logic is broken" so would be the deductive argument known as Gödel's incompleteness theorem.

    4. BTO, it is your understanding of Goedelian results that's inaccurate. The three theorems you cite prove that no single algorithm exists that can prove everything about the abstract entities in question. You are claiming that they show no algorithm exists that can prove anything about them - a much stronger claim, and clearly false.

    5. "Gödel's incompleteness theorems imply that there is no formal logical system that can prove anything nontrivial in number theory" -- that makes no sense. First Order Peano Arithmetic is able to prove things such as the Prime Number Theorem (which surely counts as nontrivial). Unless you define "nontrivial" as "independent of a given set of axioms" your comment borders on mathematical crankery.

  5. I guess that one answer that the naturalist platonist could give is that the material world is similar enough to the Forms that living in it trigger in us concepts that are similar enough to the Forms. Kinda similar to Aristotle epistemology: we don't have any contact with any subsistent Form, nor we need it. This view seems better that Aristotelian realism actually, for here you have a similar explanation of how knowledge happens and you have a sweet truth-maker of necessary truths(the Forms), which is something i think that Aristotle can't offer.

    Of course, why the material world is similar to the Forms and why it even exists are both not explained in this view since the Forms can't act, as shown. No wonder that non-naturalists platonists aways believed in very diferent things that most analytical platonists.

  6. Thomists seem to start with 'a third realm is unintelligible' but end up with 'God is in it'. Then the problem becomes not with a third realm, but with its members being inert. However, eternal act is not what makes them accessible, but eternal constitution.

  7. Prof. Feser

    This is somewhat related given his work defending Platonism, but did you hear about the death of the contemporary analytic atheist philosopher Quentin Smith? He tragically passed away recently. Both William Lane Craig and Bill Vallicella posted tributes to him. I remember you mentioned him on your blog frequently as a serious atheistic thinker who respected Theism deeply and whose work should be wrestled with. I'm sure you are aware of his landmark paper "The Meta-philosophy of Naturalism" where he launched an incisive critique against many of his fellow Naturalists and Atheists in philosophy for not taking Theism seriously in the philosophy of religion. His sentiments have echoed a lot of your work in the past about getting others to take the philosophy of religion seriously. One quote of his that I found entertaining:

    "If each naturalist who does not specialize in the philosophy of religion (i.e., over ninety-nine percent of naturalists) were locked in a room with theists who do specialize in the philosophy of religion, and if the ensuing debates were refereed by a naturalist who had a specialization in the philosophy of religion, the naturalist referee could at most hope the outcome would be that “no definite conclusion can be drawn regarding the rationality of faith,” although I expect the most probable outcome is that the naturalist, wanting to be a fair and objective referee, would have to conclude that the theists definitely had the upper hand in every single argument or debate."

    I was wondering if you were planning to write a brief tribute to him yourself, just as you did with Prof. J.H. Sobel? Your thoughts on Smith's work would be appreciated as well. Another question I had is that on your brief tribute to Sobel, you had written that "serious philosophical atheists seem very thin on the ground indeed". With Quentin Smith now passing away, I'm wondering which Atheist philosophers now left do you still consider serious thinkers. Are Graham Oppy and Paul Draper the only ones left now? If so, it does seem then that contemporary analytic atheist philosophy is pretty much in shambles.

    Smith's obituary is here:

  8. Isn't at this point that the Demiurge enters the picture?

    If I remember right, from Plato up to the Neoplatonists, everyone understood that the Forms alone, numbers included, cannot cause anything, hence the need for a causal principle bridging them all. That's precisely what the Demiurge -- or, in Christian terms (John 1:1-3), the Logos -- does.

    1. Alexander, it's impossible to reduce the Logos to the Demiurge of the Platonists and Neoplatonists, who is not a creator in the Christian sense. It's clear why the comparison is made, but it's like the attempts to assimilate the three "divine" modes of Plotinus to the Trinity. These efforts fall flat because each of these modes had aspects incompatible with God, something obviously impossible in the Blessed Trinity.

  9. @Alexander Gieg: good point, but very controversial. Lloyd Gerson, for example, holds that universals have no causal powers and that therefore Platonic Forms are not universals, because the Form F is what causes F things to be F, and so on. Fascinating stuff, and I don't know when a definitive interpretation of Plato will ever be acknowledged by all.

  10. An eternal sufficient condition cannot have a temporal effect.


  11. @Ficino: building on your phrase “Form F is what causes F things to be F”:

    1. The Form/Idea of Roundness grounds the roundness of those round things/entities existing around us (eg plates, balls, moons, planets, etc).

    2. The Form/Idea of Roundness does not necessarily result in the actual existence of any round thing/entity outside the mind because the “extramental existence of round objects” is not contained within the Idea/Form of Roundness. Our world/realm of senses could have been one in which there is no round thing at all. Hence the actual EXISTENCE of round objects/entities such as plates, balls and moons in our world/realm of senses needs to be grounded not in the Form/Idea of Roundness, but in some other Form/Idea that is relevant to the actual EXISTENCE of such round entities (and all other entities) in our world.

    3. The relevant Form/Idea to ground the extra-mental existence of all the objects/entities that happened to be existing in our world now must be the Form/Idea of EXISTENCE. Without the Form/Idea of EXISTENCE, there would be nothingness. Why is there something rather than nothing? Because there exists the Form/Idea of EXISTENCE (or BEING).

    4. So the Form/Idea of EXISTENCE/BEING enables the existence of all the contingent/conditional entities existing extra-mentally in our world now.

    5. Further analysis of this Form/Idea of Existence would lead to the conclusion “and this all classical theists understand to be God”. (adapting Aquinas’ phrase)

    (Some form of Ontological Argument can also be constructed along this line. It is a logical contradiction for the Form/Idea of Existence/Being/Pure Actuality to exist only as an idea in the mind but not existing as an actual entity outside the mind.)

    johannes y k hui

  12. My take is that there is a bigger factor at work in the concerns modern philosophers have with the idea of platonic numbers. Since Descartes and his false dichotomy of cartesian dualism, everything has become a big mess. In reality both Aristotle and Plato (and the scholastics) were essentially what we now call idealists. The material and mental worlds are not composed of different ontological primitives, the substance itself is the same.

    To explain this more clearly to the modern mind, someone like Bernardo Kastrup has a very straightforward way of expressing this, with the material world being the representation of mental processes across a transpersonal boundary. The material world is the ‘external’ image of mental processes. This fits extremely well with quantum mechanics, including the recent “No go” Bell experiments.

    Of course Kastrup’s view of God (at least as far as he will admit publicly) is closer to Averroes than to Aquinas. However we will never overcome the mistakes Descartes introduced into philosophy and even the public consciousness unless we have a clear description of this aspect. Once this hurdle is jumped, the fact that nature is deeply mathematical is self evident and no problem at all.

    1. Very interesting. I have been reading much on Kastrups idealism recently, and am now working through his new book in which he offers a novel interpretation of Shoppenhauer's metaphysics.

      Kastrup does not try to explain why mind at large' exists, and why it is dissociated into 'alters' ( individual conscious agents ), so his scheme is clearly incomplete. I hope that he is soon led to a study of classical theism so that he might perhaps combine insights from it with those of his own. I am personally impressed by the various arguments which point to a ground of being with conciousness and agency, but am far less convinced by the rest of Christian theology.

    2. This site includes another possible framing ->

      It’s far from a complete metaphysics, and arguably further from theology, but if you look at the article there about postmodernism, you get an idea about how adding an idealist framework can help to reset some of the ever increasing absurdities ?

    3. Since Kastrup’s Idealism is mentioned:

      In a response to a comment Bernard Kastrup said:

      “Personal identity, if I am right, is an illusion right now. Your desire for its preservation is just a consequence of your ego's grasping for its imaginary existence. It's a symptom of the delusion, without any true reality.”

      Sounds very much like Buddhism. My Buddhist friends would be very happy with Kastrup’s published paper mentioned in

      Note the following request by Kastrup for critique as mentioned in the link above:

      “I ask for your help in spreading the word about this white paper. I am making it available for free everywhere I can, despite the fact that it took me a lot of time and energy to put it together. If you know academics, scientists, philosophers or mathematicians who have an interest in the areas of metaphysics, ontology, panpsychism, the mind-body problem, the hard problem of consciousness, the combination problem, etc., please forward it to them and urge them to forward further. You can also download the PDF file and then upload it elsewhere in its entirety. Just do not edit it or quote it extensively out of context, please.”


      johannes y k hui

    4. I also like Kastrup, he seems to understand pretty well some problems with both materialism and panpsychism and his work helped me at least respect idealism, which i find superior to most metaphysical views. A shame that classical theism, which he likely does not know, would probably not apeal to Bernardo, i remember, for instance, a video where he denies that casuality is a real feature of reality, so someone like Aquinas would likely be convincing to him, they start with diferent presupositions.

      But i don't see why we should call Aristotle and Plato idealists. They did not believe that mind and body where as metaphysically separate as Descartes did, sure, but i never got the feeling that they thinked that all is mental.

    5. Yes I think Bernardo explicitly wants to keep his metaphysics as closely aligned to the empirical as possible, which is understandable given his mission to overturn physicalism (although he does “speculate” fairly far into the spiritual). I don’t think he does himself any favours with book titles like “Why Materialism is Baloney” etc, but equally he communicates in a way that allows people without degrees in Philosophy or Physics to understand that there are alternatives to materialism that are parsimonious and fit the abstractions of science at least as well. I only wish there were theologians with a metaphysics as clear and strong at contesting materialism, and which accords as closely as the things I have understood on my journey from atheism to Catholicism.

      As to whether Aristotle and Plato were idealists, we have had multiple mindset changes since then which make it difficult when applying labels like “dualist” or “idealist” (not helped by Descartes or Berkley). If you think about the forms, how can they function unless in a kind of idealist framework? If matter really is an ontologically separate substance from forms and mind, how do they interact? My view is that Descartes read Augustine etc and borrowed many of the old ideas, without really appreciating this underlying “idealist” context, which lead to all kinds of problems including Aquinas being seen as a dualist (when Aquinas clearly saw the body and mind as aspects of the soul).

    6. Kastrup really is very good in comunicating his ideas, even if i'am not i idealist myself i still like that his work is showing to a lot of people how science does not implies materialism at all. Just by showing how the empirical data does not say anything by itself on this question he is doing a great help.

      About Plato and Aristotle, i think that the problem is that Descartes seemed to confuse accidents with substances, that is why matter to him is extension and mind thought. If you divide things that way, them of course the interaction problem happens, these things have no point of contact.

      The classical philosophers(at least essencialists) would reject that, as your Aquinas example show. There is substances and its acidents, they are not the same. So while each substance is diferent it has a kinda of similitude in all being substances, in all participating in Being*. So idealism would not make sense to most of these thinkers, for to they things like consciousness or thought are acidents and not substances. Instead of these bizarrely separate cartesian two worlds, we have a kinda monist cosmos where there is a hierarquical chain of being, so there is no interaction problem.

      *Note that God is not part of that in the same way, of course, the exactly language to use here will vary between platonists and aristotelians

    7. @Talmid Yes well put, you are of course correct about the substances versus accidents etc.

      When I was a lot younger (as an atheist) I read some philosophy like Hegel and Jung which seemed to offer some insights, but then moved to the likes of Sartre and soon decided Philosophy was mostly about logical word games divorced from any search for truth. I then started meditating and went through Buddhism and some eastern areas, before I started reading the gospels one day, and all things changed very quickly as these simple words came alive.

      Since then my intellectual side has been mainly focused on science, and why that had lead me to an atheist view in my search for truth. This is a long rambling way of explaining why Bernardo’s Idealism is attractive to me, as it addresses many of these areas in science that made me reject religion in general. The other reasons such as suffering I resolved through contemplation and the bible, and so I’ve only fairly recently been drawn into philosophy in order to address the ways in which Bernardo’s idealism is clearly lacking from a theological perspective. I was hoping there would be a modern theologian with a metaphysics that took the church’s great and learned tradition, and fitted the likes of quantum physics and neural imaging as well as Analytic Idealism does. However whilst I feel the Thomist metaphysics could be slightly reframed and expanded in a way to fit, I don’t see anyone who has done this. My philosophy knowledge is too poor to do so myself, although I am working my way through the history of philosophy.

      My biggest question at present is about the relationship between god and the universe. Clearly he ‘gives’ being to all things, so there is a creating and sustaining ‘role’. As the first person he is unchanging and simple, so there is this mystery of being in all but different from all. He spoke the universe into existence, so is it like the relationship we have with our words and thoughts? But then the word of god is the second person, and Jesus is not the universe. The universe was created THROUGH him, is not him, but is contained within him. So is the closest way we can conceive of the reality, something like the universe being his dream?

      I’m sure this has all been addressed and apologise for my very primitive knowledge of philosophy. I’ve just reached the early scholastics so maybe that will help reconcile the different perspectives!

    8. Pretty interesting history, a lot diferent than mine own. A cool thing is that even with me never actually becaming a atheist in my life(thought i did try) and my conversion being more "intelectual", i can relate to liking idealism and eastern thought in general. I also can see how Kastrup work can appeal to someone who is more interested in science, like he himself clearly is.

      About science and thomism, i believe that there is a physicist that does try to apply thomism to his work, he goes by the name of "Quantum Thomist" i think. Not to mention, Dr. Feser himself, who published "Aristotle Revenge", from what i read about it, that book seems what you are looking for.

      About God and the universe, in classical theism the universe is real but limited and contingent, so while it is not independent of God it is a seperate thing, since God is unchanging, necessary, unlimited, non-composite etc, so the world can't be a part of Him. The idea is that God is not one with us, but that He still created and still sustain us, i think that this video would help a bit:

      Aquinas 101 is amazing by the way, specially if you are a beginner in thomism. The philosohy is a bit hard to understand if you do not already have a good familiarity with classical philosophy(as Ed said several times before), but i would say that it is worth it, so hope that you can study more!

    9. Thank you for the pointer to Aristotle’s Revenge. I’m definitely interested in how realism can survive in Quantum Physics. As far as I can tell, the recent “No Go” experiments have left very little room for realism, unless you invent countless trillions of new universes every second, or via superdeterminism where the books on my shelf were effectively written at the time of the Big Bang. It seems far more likely that matter only exists as part of an observation, and that two different observers can observe a different reality. If matter is just the representation of “the thing in itself”, then I guess there is a kind of realism there, but of course the next question is about the nature of this ‘thing in itself’ (which allows Bernardo to posit that it’s ‘mind’). This is where my question was coming from, it’s not really a question of thomist causality which I’m relatively comfortable with (although it seems closer to how science uses causality in chemistry than in modern physics). What sits between particles and god? The suggestion is that its ‘fields’ (in QFT anyway), but what are these fields from a metaphysical perspective?

      Anyway I already have Dr Fesser’s book on Aquinas which is on the ever growing list of things to read, which now includes Aristotle’s Revenge :)

    10. I don't understand much about science really, so i don't think i can help here. At least i pointed to Aristotle Revenge, so there is that :)

      Also, this is the blog from the thomist i mentioned:

      I'am sure that he and Dr. Feser could help way more that me, so good luck there!

    11. Thank you Talmid. I’ve read through much of the Quantum Thomist web pages. It’s interesting and he makes many very valid points, but I’m not convinced on his way to retain realism (not that I’m qualified to judge). I’d love to know what Aquinas thought about his mystic experience, how that sense of unity and connectedness fits his metaphysics.

  13. I was wondering what Divine likeness does to answer the question, but it seems that's what Augustine's point boils down to (sort of).

  14. I'm just curious why one would insist that something known must exert a causal influence on the one knowing? Or why the same objection doesn't come up in the case of Thomistic forms as well as Platonic Forms? Sure, an individual rabbit exerts a causal influence on me when I see it, and thus I know the individual rabbit, but when I abstract to the form "rabbit" and therefore know the form rabbit, is any Thomist going to claim that the form rabbit is exerting a causal influence on me?

    1. Yea, i also don't understand this idea. I know who Julius Cesar was and he never really helped me in doing that directly. Just like i know him indirectly, the mathematical-platonist could say that our knowledge of the Forms is indirect, it comes from our contact with things of the material world.

      Of course, how the material world is similar to something that has literally no contact with it is quite bizarre, but that is another issue.

  15. Is Robert Pasnau a Catholic? Or at least, a theist?

  16. see his dec 2020 math post. Non commercial add free