Below is the second part of Mike Wiest's review of The World as Will and Representation, Volume One. The first part is here. The next post will have his concluding thoughts. - Steve
Book 3—The Representation independent of the principle of sufficient reason: the Platonic Idea: the object of art:
On page 169 Book 3 (of Volume 1) starts:
“In the first book the world was shown to be mere representation, object for a subject. In the second book, we considered it from its other side, and found that this is will, which proved to be simply what this world is besides being representation. In accordance with this knowledge, we called the world as representation, both as a whole and in its parts, the objectivity of the will, which accordingly means the world become object, i.e., representation. Now we recall further that such objectification of the will had many but definite grades, at which, with gradually increasing distinctness and completeness, the inner nature of the will appeared in the representation, in other words, presented itself as object. In these grades we recognized the Platonic Ideas once more… In all these forms we recognize only the different aspects of the principle of sufficient reason that is the ultimate principle of all finiteness, of all individuation, and the universal form of the representation as it comes to the knowledge of the individual as such. On the other hand, the Idea does not enter into that principle; hence neither plurality nor change belongs to it. While the individuals in which it expresses itself are innumerable and are incessantly coming into existence and passing away, it remains unchanged as one and the same, and the principle of sufficient reason has no meaning for it. But now, as this principle is the form under which all knowledge of the subject comes, in so far as the subject knows as an individual, the Ideas will also lie quite outside the sphere of its knowledge as such. Therefore, if the Ideas are to become object of knowledge, this can happen only by abolishing individuality in the knowing subject. The more definite and detailed explanation of this is what will now first concern us.”
The distinct grades of objectification of the will are Plato’s Ideas, the “timeless prototypes of natural things.” Because all things are phenomena of one will, they are in some degree of relationship and harmony with one another; however, because the will is blind, the Ideas are in tension with one another, vying to manifest in phenomena. The complex balance of harmony and conflict produce phenomena in spacetime, causally ordered.
[S mentions that Platonism gets ridiculed, and it seems to be fairly unfashionable nowadays too, so I thought it might be helpful to mention a modern version of Platonism I came across recently in a paper by John D. Barrow called “Godel and Physics.” Platonism is not the subject of the paper, and is really just a manner of speaking rather than a developed theory. Still, this example made S’s Platonism a lot more digestible to my modern mind. In it, the Platonic Ideas are the symmetry groups that define modern elementary particle physics, and the different particle fields are different “representations” of the Lorentz group. “Representations” here is the actual technical math or physics term for the different “realizations” or “instantiations” of a particular symmetry group structure, so the physics meaning seems somewhat consonant with S’s usage.]
Now, there is a will-less state that reveals the Ideas in direct perception (as opposed to conceptually): the perception of the Ideas is the source of true art. Ideas are “generative,” as opposed to concepts which are abstracted from perception and “exhausted by their definition.”
S gives an interesting theory of aesthetics, the beautiful, the sublime, and art; in which music holds a special place as the direct analogue of the harmony of the different levels of objectification of the will. He develops an analogy between the hierarchy of tones in music with their foundation in the low, slow bass; and the hierarchy of levels of reality. [Here the discussion reminds me of a number of other vibration models of reality and perception, from superstring theory to the Greek Logos to kotodama, the science of spirit-sounds in Japanese Shinto.]
Book 4—The World as Will, Second Aspect: With the attainment of self-knowledge, affirmation and denial of the will-to-live:
Here S treats the ethical aspect of human behavior, the nature and extent of human freedom, and his notion of salvation:
Volume 1, page 272: “The point of view given and the method of treatment announced suggest that in this ethical book no precepts, no doctrine of duty are to be expected; still less will there be set forth a universal moral principle… Generally we shall not speak of “ought” at all, for we speak in this way to children and to peoples still in their infancy, but not to those who have appropriated to themselves all the culture of a mature age. It is indeed a palpable contradiction to call the will free and yet to prescribe for it laws by which it is to will. “Ought to will!” wooden-iron! But in the light of our whole view, the will is not only free, but even almighty; from it comes not only its action, but also its world; and as the will is, so does its action appear, so does its world appear; both are its self-knowledge and nothing more. The will determines itself, and therewith its action and this world also;”
So, from an absolute point of view outside of time, the will is free, but the will of any individual in time is determined by causes in time. There is an exception though:
Volume 1, page 287: “Man, however, is the most complete phenomenon of the will, and as was shown in the second book, in order to exist, this phenomenon had to be illuminated by so high a degree of knowledge that even a perfectly adequate repetition of the inner nature of the world under the form of the representation became possible in it… At the end of our whole discussion it will also be seen that, through the same knowledge, an elimination and self-denial of the will in its most perfect phenomenon is possible, by the will’s relating such knowledge to itself… In just this way, it exhibits the phenomena of holiness and self-denial… In this sense not only the will itself, but even man can certainly be called free, and can thus be distinguished from all other beings.”
From the point of view of causality, a person’s character is his fixed individual nature that determines the moral quality of his actions. In that context all our actions are fully determined by the intersection of our character with various circumstances (including the changing circumstance of our own growing knowledge about our own individual character as revealed by our actions). The above-mentioned freedom seems to manifest itself as a suppression of a human’s character, rather than an actual change of character, so that a sort of universal self-less personality emerges (p.403).
Page 404: “Now since, as we have seen, that self-suppression of the will comes from knowledge, but all knowledge and insight as such are independent of free choice, that denial of willing, that…only direct expression of the freedom of the will…is not to be forcibly arrived at by intention or design, but comes from the innermost relation of knowing and willing in man; hence it comes suddenly, as if flying in from without.”
[He approvingly quotes Christian descriptions of this phenomenon as the “catholic, transcendental change,” a “new birth” resulting from “grace” rather than natural causality. On page 405 he summarizes the extent of his agreement with Christian theology: “The doctrine of original sin (affirmation of the will) and of salvation (denial of the will) is really the great truth which constitutes the kernel of Christianity, while the rest is in the main only clothing and covering, or something accessory.”]
I’m generally pretty skeptical of “compatibalist” views of the relation between determinism and free will, but in S’s theory it does seem conceivable that the will that is the impetus for everything that is, when it realizes—i.e. creates—what it has willed, might wish to suppress itself, or at least its individualistic ego-centered physical-biological aspects. (Especially since it realizes all existence is “suffering,” fear and never-satisfied cravings, the dukkha of the First Noble Truth of Buddhism.) The will as thing-in-itself wills whatever it wants, freely, so when it realizes what it is—in a human brain, it may “change its mind.” The physical body may behave differently than it otherwise would have, but we might say the physical laws (for S these include causes, stimuli, and motives—all deterministic) are not changed or violated….It’s just that certain factors or forces have been reduced in amplitude, are not as strenuously fought for, but this change has no motive. Ultimately I can’t call this a deterministic theory, but it provides a scheme in which human behavior can transcend physical laws without directly violating them.
Here I’ve emphasized S’s treatment of freedom and determinism, but he also develops an interesting ethical theory. I find it to be a pretty intuitive model for moral realism. Though S says his philosophy won’t tell us how to behave, he explains that our actions nevertheless carry a real moral significance. Here is how he introduces the concept of “wrong”:
P334 “Now since the will manifests that self-affirmation of one’s own body in innumerable individuals besides one another, in one individual, by virtue of the egoism peculiar to all, it very easily goes beyond this affirmation to the denial of the same will appearing in another individual. The will of the first breaks through the boundary of another’s affirmation of will, since the individual either destroys or injures this other body itself, or compels the powers of that other body to serve his will, instead of serving the will that appears in that other body… This breaking through the boundary of another’s affirmation of will has at all times been distinctly recognized, and its concept has been denoted by the word wrong (Unrecht). For both parties instantly recognize the fact, not indeed as we do here in distinct abstraction, but as feeling.”
The feelings S is referring to are a “mental pain” of injustice in the victim and the “feeling of wrong committed” in the perpetrator. He develops this principle in a variety of cases, and distinguishes this negative ethical principle from the positive virtues that flow from the will-less consciousness. He discusses various approaches to the will-less state, and explains the distinction between the denial of the will arrived at by a clear objective perception from the apparent denial of the “will-to-live” in suicide. I won’t dwell on his ethical theory because I don’t feel competent to compare it to other approaches and attempt an overall assessment. But again, it seems to offer an intuitive metaphysics for a kind of moral realism—but with a more qualified freedom than one might expect from a moral realist theory.
(S’s final chapter of Volume 1 is an appendix on Kant, sketching K’s principal merits—which S earnestly considers to be epoch-making, as well as detailing his errors. I think Volume 2 is essentially further elaboration of the theory presented in Volume 1, and responses to objections composed over 30 years between the publication of Vols. 1 and 2.)
Friday, November 30, 2007
Tuesday, November 27, 2007
Guest Post: Mike's Review of Schopenhauer
I am happy to introduce a guest post below, authored by Mike Wiest. In a discussion in the comment thread of an earlier post (“Pan-Intentionality”), Mike mentioned his recent reading of Arthur Schopenhauer’s work, and talked about connections he saw between Schopenhauer and the topics that he, Justin and I were talking about. Below is the first of a series of three posts containing Mike’s summary review and reactions to Volume One of The World as Will and Representation. I’d also like to note that Justin, in a similar spirit, also brought up Nietzsche in the discussion, and he followed up with a post on the metaphysics of Nietzsche’s concept of the Will to Power at his blog, Panexperientialism. Here's Mike--
The World as Will and Representation, Volume 1
Schopenhauer claims at the outset that his entire book was aimed at and necessary to communicating a single thought. He states further that because of the organic inter-relationship among the aspects of that single thought, his book must be read twice to be fully comprehended (as, he says, with a great musical composition). I only read it once, but I think the thought is something like this: We can know Kant’s unknowable thing-in-itself, the true nature of the world, by direct conscious perception; and what this experience discloses is that all of our individual wills and consciousnesses are “phenomena” of a single, unconscious, universal will outside of time.
Book 1—Representation:
The beginning of philosophy for S is to realize that this world of objects is our representation, and furthermore that all objects are for a subject: all objects are subject-objects. He thinks that only Kant’s teaching can effectively produce the insight that removes the “child-like realism in which we are all born.” And thus “My philosophy starts from Kant’s, and therefore presupposes a thorough knowledge of it.” In particular, Kant taught us the distinction between our experience of an object, the phenomenon, and its true inner nature or reality, the thing-in-itself. (Despite this statement I think one could read and enjoy S without having read Kant: S’s Kant is easier to understand than Kant in his own words.)
But Kant missed that the a priori framework for all experience (including time, space, and matter understood as the principle of causality) are all manifestations of one principle of sufficient reason, which says every event has a cause and implies universal determinism (—but this is not S’s last word on freedom!). This causal law and determinism apply to all objective phenomena, meaning that every event in spacetime has a cause in spacetime, which is the reason the event happened then and there. But because causes and effects in spacetime constitute the form of our subjective understanding of objects (they are prerequisites for being an object), objective phenomena are all for-a-subject. It may not be so difficult for a panpsychist to accept that all matter has a subjective aspect; the hard part is accepting that we cannot think of the thing-in-itself as matter (event protoconscious matter) evolving in spacetime. Again, the matter model is perfectly effective empirically, for describing the network of objects and causes, but we have no inkling of the thing-in-itself behind our representations (this will change later in the book). Thus, our causal reasoning cannot be used to explain the origin or form of the fundamental forces, nor anything outside the causal network. Similarly, there can be no question of a causal relationship between subject and object, in either direction. Rather, subject and object are necessary poles of all objective existence in spacetime.
Now, S thinks that Kant and many other philosophers have been confused about perception and its relation to concepts and rational thought. For S perception is already intellectual (or cognitive). In particular, perception is immediate causal understanding (an intuition based on normal context, called illusion when wrong). For example, rather than merely sensing a two dimensional pattern of colors, I perceive “(this sensation in my visual field is caused by) an object nearby in 3D space in front of me.” This faculty we have in common with animals. Reason is a basically uniquely human faculty that uses concepts abstracted from perception to reach conclusions about past and future events (called error when wrong). This ability liberates us from the present. S has a nice pictorial way of representing reasoning (using Venn diagrams) as a procedure of passing between different concepts by means of what they have in common. He claims this simple framework can account for all our reasoning. Kant’s error in this context is roughly that he takes concepts to be primary and perceptions are to be understood in terms of concepts, whereas S teaches that all original evidence lies in perception, and concepts merely systematize, fix, and communicate evidence from perception.
[I’m not sure yet how I feel about the relational interpretation of quantum mechanics. But from this line in the Stanford Encyclopedia article about it, it seems to be a specific instantiation of S’s doctrine that objects and their various properties exist only relative to a particular observer: “Quantum mechanical relationalism is the observation that there are no absolute properties: properties of a system S are relative to another system O with which S is interacting.”]
Book 2—Will:
It’s what Kant missed when he said the thing-in-itself is absolutely unknowable. Considering things objectively, from the outside, we can never fathom their inner nature. But S points out that there is one thing whose inner nature we have special access to. S says that in reflecting on the contents of our own consciousness we find something absolutely distinct from all the objects in our representation (i.e. even subject-objects), namely feelings that reflect our will.
Volume 2 page 202: “…Not only willing and deciding in the narrowest sense, but also all striving, wishing, shunning, hoping, fearing, loving, hating, in short all that directly constitutes our own weal and woe, desire and disinclination, is obviously only affection of the will, is a stirring, a modification, of willing and not-willing, is just that which, when it operates outwards, exhibits itself as an act of will proper.”
Our will is often unconscious, but in experience it manifests pleasurable and painful states where our preferences are apparent, like anger and lust. Of course the various passions are usually experienced as entangled with our representations of our body and other bodies in spacetime, but for S the road to truth is to clarify the distinction between them. The point is to realize that our will is our deepest reality, our innermost essence (not our intellect, which serves the will, and is in fact “objectified” will). The next—big—step is to see that my inner nature, my true existence, is identical with the thing-in-itself of the whole world.
So we are to understand that the apple’s falling and the seedling’s sprouting are impelled by the same will (though unconscious) that ultimately drives us. This world is the objectification, or mirror, of will. We cannot consider it as multiple because space is the principle of individuation, which exists only in our representation. It is outside of all causation, but the world of causes in beginningless time arises out of it. Grades or levels of objectification of will correspond to inexplicable laws or entities that must be presupposed in our causal explanations. For example, physical causes, stimuli, and motives all necessarily bring about particular effects in particular circumstance, but represent different levels of objectification of will. Physical causes lead to an effect that is of the same physical magnitude as the cause, whereas stimuli are small causes that lead to large effects, and motives are causes that have passed through knowledge, i.e. through a conscious brain process. [To me this is account of the objective world as a shell whose inner being is mental in nature is reminiscent of Gregg Rosenberg’s contemporary account, in which causality is carried by experiences corresponding to a hierarchy of natural individuals, and the temporally ordered flow of events arises from some kind of meta-temporal nexus of events.]
The thing in itself, the universal will outside of time, is unconscious and purposeless, a blind “procreant urge of the world” (that’s Whitman, not S). But we can also say that it wills to live:
Volume 1, page 274: ‘The will, considered purely in itself, is devoid of knowledge, and is only a blind, irresistible urge, as we see it appear in inorganic and vegetable nature and in their laws, and also in the vegetative part of our own life. Through the addition of the world as representation, developed for its service, the will obtains knowledge of its own willing and what it wills, namely that this is nothing but this world, life, precisely as it exists. We have therefore called the phenomenal world the mirror, the objectivity, of the will; and as what the will wills is always life, just because this is nothing but the presentation of that willing for the representation, it is immaterial and a mere pleonasm if, instead of simply saying “the will,” we say “the will-to-live.” ‘
We are the highest level of reflection (i.e. objectification) of the will.
The World as Will and Representation, Volume 1
Schopenhauer claims at the outset that his entire book was aimed at and necessary to communicating a single thought. He states further that because of the organic inter-relationship among the aspects of that single thought, his book must be read twice to be fully comprehended (as, he says, with a great musical composition). I only read it once, but I think the thought is something like this: We can know Kant’s unknowable thing-in-itself, the true nature of the world, by direct conscious perception; and what this experience discloses is that all of our individual wills and consciousnesses are “phenomena” of a single, unconscious, universal will outside of time.
Book 1—Representation:
The beginning of philosophy for S is to realize that this world of objects is our representation, and furthermore that all objects are for a subject: all objects are subject-objects. He thinks that only Kant’s teaching can effectively produce the insight that removes the “child-like realism in which we are all born.” And thus “My philosophy starts from Kant’s, and therefore presupposes a thorough knowledge of it.” In particular, Kant taught us the distinction between our experience of an object, the phenomenon, and its true inner nature or reality, the thing-in-itself. (Despite this statement I think one could read and enjoy S without having read Kant: S’s Kant is easier to understand than Kant in his own words.)
But Kant missed that the a priori framework for all experience (including time, space, and matter understood as the principle of causality) are all manifestations of one principle of sufficient reason, which says every event has a cause and implies universal determinism (—but this is not S’s last word on freedom!). This causal law and determinism apply to all objective phenomena, meaning that every event in spacetime has a cause in spacetime, which is the reason the event happened then and there. But because causes and effects in spacetime constitute the form of our subjective understanding of objects (they are prerequisites for being an object), objective phenomena are all for-a-subject. It may not be so difficult for a panpsychist to accept that all matter has a subjective aspect; the hard part is accepting that we cannot think of the thing-in-itself as matter (event protoconscious matter) evolving in spacetime. Again, the matter model is perfectly effective empirically, for describing the network of objects and causes, but we have no inkling of the thing-in-itself behind our representations (this will change later in the book). Thus, our causal reasoning cannot be used to explain the origin or form of the fundamental forces, nor anything outside the causal network. Similarly, there can be no question of a causal relationship between subject and object, in either direction. Rather, subject and object are necessary poles of all objective existence in spacetime.
Now, S thinks that Kant and many other philosophers have been confused about perception and its relation to concepts and rational thought. For S perception is already intellectual (or cognitive). In particular, perception is immediate causal understanding (an intuition based on normal context, called illusion when wrong). For example, rather than merely sensing a two dimensional pattern of colors, I perceive “(this sensation in my visual field is caused by) an object nearby in 3D space in front of me.” This faculty we have in common with animals. Reason is a basically uniquely human faculty that uses concepts abstracted from perception to reach conclusions about past and future events (called error when wrong). This ability liberates us from the present. S has a nice pictorial way of representing reasoning (using Venn diagrams) as a procedure of passing between different concepts by means of what they have in common. He claims this simple framework can account for all our reasoning. Kant’s error in this context is roughly that he takes concepts to be primary and perceptions are to be understood in terms of concepts, whereas S teaches that all original evidence lies in perception, and concepts merely systematize, fix, and communicate evidence from perception.
[I’m not sure yet how I feel about the relational interpretation of quantum mechanics. But from this line in the Stanford Encyclopedia article about it, it seems to be a specific instantiation of S’s doctrine that objects and their various properties exist only relative to a particular observer: “Quantum mechanical relationalism is the observation that there are no absolute properties: properties of a system S are relative to another system O with which S is interacting.”]
Book 2—Will:
It’s what Kant missed when he said the thing-in-itself is absolutely unknowable. Considering things objectively, from the outside, we can never fathom their inner nature. But S points out that there is one thing whose inner nature we have special access to. S says that in reflecting on the contents of our own consciousness we find something absolutely distinct from all the objects in our representation (i.e. even subject-objects), namely feelings that reflect our will.
Volume 2 page 202: “…Not only willing and deciding in the narrowest sense, but also all striving, wishing, shunning, hoping, fearing, loving, hating, in short all that directly constitutes our own weal and woe, desire and disinclination, is obviously only affection of the will, is a stirring, a modification, of willing and not-willing, is just that which, when it operates outwards, exhibits itself as an act of will proper.”
Our will is often unconscious, but in experience it manifests pleasurable and painful states where our preferences are apparent, like anger and lust. Of course the various passions are usually experienced as entangled with our representations of our body and other bodies in spacetime, but for S the road to truth is to clarify the distinction between them. The point is to realize that our will is our deepest reality, our innermost essence (not our intellect, which serves the will, and is in fact “objectified” will). The next—big—step is to see that my inner nature, my true existence, is identical with the thing-in-itself of the whole world.
So we are to understand that the apple’s falling and the seedling’s sprouting are impelled by the same will (though unconscious) that ultimately drives us. This world is the objectification, or mirror, of will. We cannot consider it as multiple because space is the principle of individuation, which exists only in our representation. It is outside of all causation, but the world of causes in beginningless time arises out of it. Grades or levels of objectification of will correspond to inexplicable laws or entities that must be presupposed in our causal explanations. For example, physical causes, stimuli, and motives all necessarily bring about particular effects in particular circumstance, but represent different levels of objectification of will. Physical causes lead to an effect that is of the same physical magnitude as the cause, whereas stimuli are small causes that lead to large effects, and motives are causes that have passed through knowledge, i.e. through a conscious brain process. [To me this is account of the objective world as a shell whose inner being is mental in nature is reminiscent of Gregg Rosenberg’s contemporary account, in which causality is carried by experiences corresponding to a hierarchy of natural individuals, and the temporally ordered flow of events arises from some kind of meta-temporal nexus of events.]
The thing in itself, the universal will outside of time, is unconscious and purposeless, a blind “procreant urge of the world” (that’s Whitman, not S). But we can also say that it wills to live:
Volume 1, page 274: ‘The will, considered purely in itself, is devoid of knowledge, and is only a blind, irresistible urge, as we see it appear in inorganic and vegetable nature and in their laws, and also in the vegetative part of our own life. Through the addition of the world as representation, developed for its service, the will obtains knowledge of its own willing and what it wills, namely that this is nothing but this world, life, precisely as it exists. We have therefore called the phenomenal world the mirror, the objectivity, of the will; and as what the will wills is always life, just because this is nothing but the presentation of that willing for the representation, it is immaterial and a mere pleonasm if, instead of simply saying “the will,” we say “the will-to-live.” ‘
We are the highest level of reflection (i.e. objectification) of the will.
Saturday, November 17, 2007
Panpsychism in the NY Times Magazine
Discussed in a short essay by writer Jim Holt. Overall, a nice advertisement for the idea, with mentions of Nagel, Chalmers, and Galen Strawson. If only he could have resisted the urge to use the "thinking rock" trope!
Tuesday, November 13, 2007
Dreyer's Internal Relativity
In recent years, a new school of quantum gravity research has come into view. The research programs in this group attempt to demonstrate that neither the matter fields nor the space-time geometry described by our present theories are fundamental, but instead both co-emerge from a pre-geometric quantum mechanical foundation. (Links to my prior posts on this research are at the end of this post). Olaf Dreyer is a theoretician working in this mode. He recently presented this paper, “Why Things Fall”, which nicely summarized his work to-date (hat tip: this thread maintained by marcus at Physics Forums).
What helps make the paper accessible is that Dreyer’s approach has been to work at a very stylized conceptual level. He wants to show how the path to a full theory should go, with the goal of filling in crucial details later. It is clear that this kind of theory has a long way to go, in particular to show that Einstein’s equations will specifically emerge.
In the introduction, Dreyer describes the approach where gravity is not assumed at the outset but is emergent. He breaks this down further by discussing the constraint that there is to be is no clean distinction between the emergent gravity and matter degrees of freedom (as opposed to an approach like early string theory where the graviton emerged as part of the particle family). Rather, it is only through the matter degrees of freedom that we infer the geometry. He says: “…we are taking seriously the fact that we only know geometry through matter…geometry alone is not accessible to us. (p.2)” This description of the emergence of geometry is in contrast to an approach like loop quantum gravity, where the space-time geometry of general relativity is taken as given and then quantized. What makes the theory a quantum theory of gravity is that the matter degrees of freedom and inferred geometry will emerge from a foundation which is quantum mechanical. One consequence of adopting a QM system as fundamental is that background time is assumed at this foundational level, although it will have no relationship to emergent space-time. I have no problem with this: something has to be fundamental and I think time and asymmetric causality are good candidates for this role.
The term “internal relativity” is meant to stress a key point: we ask what geometry obtains from observed degrees of freedom from a point of view within the system. Dreyer believes that if we do this, relativity naturally will emerge.
As a prepatory example, Dreyer shows (in section 3) how something like this happens in a classical theory. Specifically, if we start with an electro-magnetic field (on a Newtonian background of absolute space and time), we can see how special relativity emerges from considering how the dynamics of charged particles gives rise to contraction/dilation effects from a point of view inside the system.
Section 4 presents the main model of the paper. Dreyer begins with a simple quantum mechanical system in a ground state (level 0). Then he allows for excitations (traveling spin waves in the model). This is level 1, and the excitations are meant to be analogues of elementary particles of our world. Level 2 is given by bound states of these excitations. These bound states are meant to be analogues of the solid objects of our world. They do not leave the parameter on ground state of level 0 unchanged. Dreyer analyzes the effect of the objects on the distribution of the level 0 parameter and is able to derive Newton’s law of gravitation between the objects in a low velocity approximation. He then says the presence of Newtonian gravity means that the geometry seen by internal observers will be not flat but curved (a curved Lorentzian manifold). So while Newtonian gravity was derived, the overall framework implies something which goes beyond Newtonian gravity. He notes that the model falls short of showing that the gravitational mass implied for the bound objects is actually the same as the inertial mass.
Section 5 concludes with some discussion. Dreyer reiterates the concepts involved in having matter degrees of freedom and gravitation emerge from a fundamental level that has distinct degrees of freedom. He discusses how certain problems don’t arise in this conceptual framework, such as the “problem of time” which arises when one quantizes space-time, and the problem of incorrect predictions for the value of the cosmological constant. He also discusses some very preliminary ideas for observable consequences which may follow from this kind of theory.
Emergent Quantum Gravity Research Series (in chronological order):
What’s New in Quantum Gravity
A section of Lee Smolin’s recent book discusses new approaches.
Causality First
Rafael Sorkin’s Causal Sets and Fotini Markopoulou’s Quantum Causal Histories.
Emerging From the Noise
More on Markopoulou’s approach.
Caution: Universe under Construction
The Causal Dynamical Triangulation program.
Geometrogenesis
More papers from Markopoulou and colleagues.
In the Beginning was the Qubit
Seth Lloyd’s quantum computing-inspired take on quantum gravity.
What helps make the paper accessible is that Dreyer’s approach has been to work at a very stylized conceptual level. He wants to show how the path to a full theory should go, with the goal of filling in crucial details later. It is clear that this kind of theory has a long way to go, in particular to show that Einstein’s equations will specifically emerge.
In the introduction, Dreyer describes the approach where gravity is not assumed at the outset but is emergent. He breaks this down further by discussing the constraint that there is to be is no clean distinction between the emergent gravity and matter degrees of freedom (as opposed to an approach like early string theory where the graviton emerged as part of the particle family). Rather, it is only through the matter degrees of freedom that we infer the geometry. He says: “…we are taking seriously the fact that we only know geometry through matter…geometry alone is not accessible to us. (p.2)” This description of the emergence of geometry is in contrast to an approach like loop quantum gravity, where the space-time geometry of general relativity is taken as given and then quantized. What makes the theory a quantum theory of gravity is that the matter degrees of freedom and inferred geometry will emerge from a foundation which is quantum mechanical. One consequence of adopting a QM system as fundamental is that background time is assumed at this foundational level, although it will have no relationship to emergent space-time. I have no problem with this: something has to be fundamental and I think time and asymmetric causality are good candidates for this role.
The term “internal relativity” is meant to stress a key point: we ask what geometry obtains from observed degrees of freedom from a point of view within the system. Dreyer believes that if we do this, relativity naturally will emerge.
As a prepatory example, Dreyer shows (in section 3) how something like this happens in a classical theory. Specifically, if we start with an electro-magnetic field (on a Newtonian background of absolute space and time), we can see how special relativity emerges from considering how the dynamics of charged particles gives rise to contraction/dilation effects from a point of view inside the system.
Section 4 presents the main model of the paper. Dreyer begins with a simple quantum mechanical system in a ground state (level 0). Then he allows for excitations (traveling spin waves in the model). This is level 1, and the excitations are meant to be analogues of elementary particles of our world. Level 2 is given by bound states of these excitations. These bound states are meant to be analogues of the solid objects of our world. They do not leave the parameter on ground state of level 0 unchanged. Dreyer analyzes the effect of the objects on the distribution of the level 0 parameter and is able to derive Newton’s law of gravitation between the objects in a low velocity approximation. He then says the presence of Newtonian gravity means that the geometry seen by internal observers will be not flat but curved (a curved Lorentzian manifold). So while Newtonian gravity was derived, the overall framework implies something which goes beyond Newtonian gravity. He notes that the model falls short of showing that the gravitational mass implied for the bound objects is actually the same as the inertial mass.
Section 5 concludes with some discussion. Dreyer reiterates the concepts involved in having matter degrees of freedom and gravitation emerge from a fundamental level that has distinct degrees of freedom. He discusses how certain problems don’t arise in this conceptual framework, such as the “problem of time” which arises when one quantizes space-time, and the problem of incorrect predictions for the value of the cosmological constant. He also discusses some very preliminary ideas for observable consequences which may follow from this kind of theory.
Emergent Quantum Gravity Research Series (in chronological order):
What’s New in Quantum Gravity
A section of Lee Smolin’s recent book discusses new approaches.
Causality First
Rafael Sorkin’s Causal Sets and Fotini Markopoulou’s Quantum Causal Histories.
Emerging From the Noise
More on Markopoulou’s approach.
Caution: Universe under Construction
The Causal Dynamical Triangulation program.
Geometrogenesis
More papers from Markopoulou and colleagues.
In the Beginning was the Qubit
Seth Lloyd’s quantum computing-inspired take on quantum gravity.
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