Author and self-proclaimed metaphysical speculator⁽¹⁾ Bernardo Kastrup attempts to solve the mind-body problem by embracing philosophical idealism. His basic insight is sound, but the way he defends it is flawed, and some details of his theory don’t support his aim. This essay shows how, with a little tweaking, his insight can be salvaged. But be warned: it gets a little dense.

First, some background. The mind-body problem, recently renamed the “hard problem”⁽²⁾, is the problem of how the ability to be conscious (mind) is related to entirely unconscious matter (body).⁽³⁾ Historically there have been two broad categories of answers, dualism and monism. Dualism asserts that mind and body are two different types of substances. Mind has the ability to be conscious but lacks spatial extension, and body has spatial extension but lacks the ability to be conscious.⁽⁴⁾ Dualism, although favored by some theologians, is unsatisfactory because it fails to explain how an immaterial substance can have any interaction with or effect on a material substance, and vice versa. Monism, on the other hand, asserts that there is basically only one type of substance. One of its variants, materialism, says that the basic substance is matter. Another, idealism, says that the basic substance is mind.

Materialism is unsatisfactory as a metaphysics because it can’t explain how unconscious matter gives rise to experience. Historically the alternative to materialism—at least for those who prefer monism over dualism—has been idealism. But idealism is equally unsatisfactory, as I shall endeavor to show. (I discuss a third alternative, dual-aspect monism, below.)

Idealism is not, in its philosophical form, the espousal of high or noble principles such as truth, justice, loyalty, compassion, and the like. Philosophical idealism would better be called “idea-ism,” as it is the doctrine that everything is basically ideas, that reality at its core is mental. It has a long and varied history in western philosophy from Plato onward to Leibniz, Berkeley, Kant, the German idealists culminating in Hegel and a number of now-forgotten British and American idealists who followed Hegel.⁽⁵⁾ It has an even longer history in Indian philosophy, going back to the Upanishads and onward through Shankara’s Advaita Vedanta and, more recently, the teachings of gurus such as Sri Ramakrishna, Sri Aurobindo and others.⁽⁶⁾ I bring up the Indian tradition because it seems to be the inspiration for Kastrup’s idealism.

That inspiration would be fine, except that in a recent paper Kastrup attempts to go beyond mystical intuition to present a logically rigorous defense of idealism, and in fact a particular type of idealism, absolute idealism, the claim that being is ultimately comprehensible as an all-inclusive whole.⁽⁷⁾ Kastrup wants to demonstrate that, as he puts it, “there is only universal consciousness.”⁽⁸⁾ His aim is to show “how the most parsimonious possible ontology can be derived, through rigorous steps of reasoning, from canonical empirical facts available to observation.”[p. 2] Unfortunately neither his facts nor his reasoning holds up to scrutiny. Here are just a few examples.

Kastrup starts by listing nine “empirical facts accessible to anyone through simple observation.”[p. 2] These are to function as premises for his argument. Most are not controversial, but some are. Let’s take his Fact 7:

Fact 7: a nervous system has the same essential nature — that is, it belongs to the same ontological class — as the rest of the physical universe. After all, nervous systems are physical systems. They are composed of the same types of basic subatomic particles that make up the universe as a whole.[p. 2]

This is an assumption, not a fact. There are actually two problems here. The first is that the composition of nervous systems is not accessible through simple observation. Scientists and medical researchers investigating nervous systems reliably observe certain images through microscopes and certain readings on rather complex instruments. It is a plausible theory, based on these observations, that nervous systems are composed of subatomic particles; and it is indeed the most plausible theory so far. But it is nevertheless a theory and certainly not accessible through simple observation. Similarly, the composition of the universe as a whole is a theory, not a fact. Even worse, the assumption that the universe, including nervous systems and the farthest stars, is the same throughout is just that, an assumption. It underlies the scientific method but is not demonstrated by that method. So Kastrup’s alleged fact, although plausible, is hardly an empirical one accessible to anyone through simple observation.

His reasoning is even more suspect. Take his Inference 1, which is based on Facts 1 and 2.

Fact 1: there is subjective experience. This is the primary and incontrovertible datum of existence.[p. 2]

Fact 2: from Fact 1, we know that there is that which experiences, since experience entails an experiencer. Notice that I am not, at least for now, passing any judgment or making any assumption about the fundamental nature or boundaries of that which experiences. … For ease of reference, I will henceforth refer to ‘That Which Experiences’ simply as ‘TWE.'[p. 2]

Inference 1: the most parsimonious ontological underpinning for Facts 1 and 2 is that experiences are patterns of excitation of TWE. This avoids the need to postulate two different ontological classes for TWE and experiences, respectively. As excitations of TWE, experiences aren’t distinct from it in exactly the same way that ripples aren’t distinct from water, or that a dance isn’t distinct from the dancer. … There is nothing to experience but TWE ‘in motion.’ Ripples, dances and experiences are merely patterns of excitation of water, dancers and TWE, respectively.[p. 3]

Inference 1 has some problems.

• The phrase “subjective experience” in Fact 1 is redundant, as all experience is subjective, accessible directly only by the one who is experiencing. I suppose this is just a quibble, but one would expect a bit more precision from a person who claims to make a rigorous argument. More seriously, it can be argued that the primary datum of existence is not that there is experience but that there is a world. Only after some reflection do we realize that it is we who experience the world.
• Fact 2 is not something accessible through simple observation, it is an analytical truth. This is also just a quibble, though. The interesting part of Fact 2 is that Kastrup says he makes no assumptions about the nature of that which experiences (TWE).
• But in Inference 1 he does make an assumption about TWE. He says it is something excitable. It can be in motion. It is a sort of medium that contains or is composed of patterns of excitation.

No doubt what we experience is constantly in motion and much of it appears in patterns. But to claim that what experiences all that motion is itself in motion is not an inference; it is just an assertion. Kastrup claims that the assertion is based on ontological parsimony, but gives no evidence for that claim. In fact, what he does here is to assume what he wants to prove. His goal is ontological parsimony, so he assumes ontological parsimony to justify the inference to his goal of ontological parsimony. This is not a sound logical move.

Kastrup says that TWE is “an indisputable empirical fact … as opposed to abstractions of thought.”[p. 11] But it is not an empirical fact. Even on his own terms (“experience entails an experiencer”) it is something inferred. Given that his inference is faulty, TWE is just an assertion, and far from indisputable.

His Inference 2, which is based on Fact 4, has problems as well.

Fact 4: there is at least a partial correlation between measurable electrochemical activity in a person’s nervous system and the person’s private experiences.[p. 2]

Inference 2: from Fact 4, we know that a nervous system is sentient. … Somehow, the activity of these systems is accompanied by inner experience. One possibility is that there is something about the particular structure or function of nervous systems that constitutes sentience. However, it is impossible to conceive — even in principle — of how or why any particular structural or functional arrangement of physical elements would constitute sentience …. This is a well-known problem in neuroscience and philosophy of mind, often referred to as the ‘hard problem of consciousness.’ … It remains conceivable that physical arrangements could still modulate experience, without constituting it, if one postulates some form of dualism. But even if this hypothesis turns out to be coherent, it would still leave That Which Experiences entirely unexplained, since TWE would be that which is modulated (Inference 1). From all this we must conclude that TWE is uncaused, irreducible. It simply is. Technically, we say that TWE is an ontological primitive.[p. 3]

How does he get from the assertion that nerve activity and experience are correlated to the conclusion that TWE is uncaused and irreducible? That is quite a leap. Let’s analyze the argument in detail.

• He asserts that “from Fact 4, we know that a nervous system is sentient.” Already there is a problem, because it is not the nervous system that is sentient but the person or organism whose nervous system it is.
• He then adds an additional premise, one not stated in his list of facts, that it is impossible to conceive how arrangements of physical stuff could result in sentience. But he gives no evidence for the assertion except citing an authority or two. As a matter of fact, it is quite controversial, and there is a large body of literature devoted to arguments pro and con.⁽⁹⁾
• He alludes to dualist explanations of the mind-body problem and claims that they might explain how physical stuff could modulate experience but also claims that TWE would be unexplained. His justification for the latter assertion is his Inference 1, which we have just found to be faulty.
• He concludes that since TWE is unexplained both under monistic materialism and under dualism, it must be an uncaused, irreducible ontological primitive.

All three of his premises are flawed, two being entirely unjustified. Hence, the conclusion does not follow. Once again Kastrup assumes in his premises what he wants to prove. He wants to say that the only explanation for TWE is monistic idealism, but assumes without justification that no other explanations suffice. He begs the question, committing the fallacy of citing as a premise what is in dispute.

OK, that’s enough. There are many more nonsequiturs, unexamined premises and the like. Poking holes in this guy’s argument is like shooting fish in a barrel. The conclusion to be drawn, however, is not necessarily that Kastrup’s metaphysics is wrong. It may be simply that logical derivation is a poor way to ground or justify metaphysics.

Kastrup is trying to get at something important. Even if his derivation is flawed there may be something worthwhile in his conclusion, so let’s start there and see if it makes sense. Here is a summary of his thesis:

I argue for a coherent idealist ontology [which] can be summarized as follows: there is only universal consciousness. We, as well as all other living creatures, are but dissociated alters [i.e. alter egos] of universal consciousness, surrounded like islands by the ocean of its mentation. The inanimate universe we see around us is the extrinsic view of thoughts and emotions in universal consciousness. The living creatures we share the world with are the extrinsic views of other dissociated alters of universal consciousness. A physical world independent of consciousness is a mistaken intellectual abstraction.[p. 1]

The statement that there is only universal consciousness puts Kastrup firmly in the absolute idealist camp. He explains reality in terms of ideas—thoughts and emotions—in universal consciousness. By saying “there is only,” he asserts a kind of monism, saying that all that exists is something he calls “universal consciousness.” By that phrase he means TWE, that which experiences. He says “‘Consciousness’ is the ordinary English word that best fits what I mean by TWE.”[p. 11]

(As an aside, I think “consciousness” is actually a terrible word for TWE. It has too many other meanings, ranging from merely being awake to being conscious of things in an ordinary sort of way to being a conscious self. The term “consciousness” as a synonym for TWE conceived of as the ground of all being is misleading. Its meaning is certainly far from just being able to detect your surroundings well enough to navigate around. In another place Kastrup uses the term “mind-at-large,” which is much better.)

So Kastrup is a monist. Now, monism can be of two kinds, which we might call, following the analytic philosophers, Type monism and Token monism. The distinction between a type and its tokens is an ontological one between a general sort of thing and its particular concrete instances. The sentence “A rose is a rose is a rose” contains eight separate tokens, words as individual collections of letters, but only three types, words as things that convey meaning. The word “rose” is one type that appears three times in the sentence; that is, there are three tokens of it.⁽¹⁰⁾ Type monism would assert that although there are lots of different things in the world, they are all made of the same type of stuff or all fit into the same ontological category. Token Monism would assert that, appearances to the contrary, there is actually only one thing.

Materialism is a Type monism. No materialist asserts that there is only one material thing; instead, all things are taken to be of the same type, namely physical matter. Some idealisms, notably that of Bishop Berkeley, are Type monisms, asserting that there are many things, each of which is of the same type, something perceived by the mind via the senses. Berkeley says that such sensible qualities cannot exist apart from being perceived.⁽¹¹⁾ Kastrup, however, is a Token monist. In another work he says “consciousness is unitary and essentially undivided. … I call this unitary consciousness ‘mind-at-large’. … the universe as a whole has subjective inner life.”⁽¹²⁾

Kastrup calls his work a defense of nondualism.⁽¹³⁾ He is a modern apologist for the ancient Indian philosophy Advaita Vedanta. “Advaita” means not two, or non-dual; and “Vedanta” literally means the end of the Vedas. The Vedas are ancient religious texts of India, and their end is the Upanishads, philosophical texts based on them.⁽¹⁴⁾ Advaita Vedanta is a nondualist interpretation of certain themes in the Upanishads, the main point of which is

a consideration of the relation between Brahman, the Holy Power spoken of in the Upanishads … as sustaining and/or informing the cosmos, and the self, or atman. Some Upanishadic texts … assert that in some sense Brahman and atman are one.⁽¹⁵⁾

Here are some representative passages that make that assertion:

“This whole universe is Brahman.”⁽¹⁶⁾

“This finest essence,– the whole universe has it as its Self: That is the Real: That is the Self: That you are!”⁽¹⁷⁾

“This Self is Brahman indeed.”⁽¹⁸⁾

And that’s what Kastrup is getting at when he says there is only the mind-at-large. The whole universe, Brahman, is a self, atman. The universe as a whole, having a subjective inner life, is like a living being. Everything in the universe is something contained in the mind-at-large. All things, nonliving and living, inanimate and animate, are things that the mind-at-large thinks of or feels; in other words, is conscious of.

Kastrup explains the difference between what is not living and what is living in an interesting way. Both are in the mind-at-large, but in different ways. Inanimate things are ideas in this being’s mind and living organisms such as human beings are dissociated alter egos of this being, rather like split personalities of a person suffering from dissociative identity disorder.[p. 4] Each alter ego perceives the world, but only from its own point of view rather than that of the mind-at-large. Each alter ego is like a little piece of the cosmic ego, mind-at-large, which perceives the whole universe.

What each alter ego perceives as separately existing things and as living beings are extrinsic views either of mental activities within the mind-at-large or of other alter egos (which I presume are also mental activities within the mind-at-large). By “extrinsic” Kastrup appears to mean exterior. The mind-at-large thinks of nonliving things such as rocks. The rocks are ideas in the mind-at-large; they are interior or intrinsic to that mind. What we alter egos see as rocks is the exterior, the extrinsic view, of mind-at-large’s ideas of rocks. Living beings are dissociated entities that have an interior or intrinsic view, their own view of the world, and an appearance to other alter egos, an exterior or extrinsic view. That is Kastrup’s ontology in a nutshell, explaining how everything exists in the mind-at-large.

But consider this ontology carefully. Some entities, the inanimate ones, have only an exterior. The mind-at-large thinks of them—i.e., they are objects that the mind-at-large is conscious of—but they themselves are not conscious of anything. We alter egos are conscious of them, but they are in no way conscious of us. Other entities, the living ones, have both an exterior and an interior. They are objects that the mind-at-large is conscious of, and they themselves are conscious of things. We alter egos are conscious of them, and they are or can be conscious of us. In effect Kastrup posits two categories of things, bodies with no mind and bodies with mind. Despite being dressed up in monistic terms, his ontology is dualist!

If we want a truly monist ontology, we must look elsewhere. Fortunately, there is a better one. It is both Type and Token monist, it accounts for the undeniable plurality that we find in the world, and it is true to the unitary mystical insight of the Upanishads. That ontology is based on the process metaphysics of Alfred North Whitehead.

I have written about Whitehead’s metaphysics on several occasions: in my book How To Be An Excellent Human and in some blog essays, notably “Dead or Alive?” and “In Defense of Panpsychism.” Here I give just a short summary.

Whitehead’s ontology is one of process. The fundamental units of reality, in his view, are occasions, not inert particles. Occasions are quite tiny. He wrote at a time when quantum mechanics was being developed, and no doubt the mysterious behavior of reality at the subatomic level informed his thinking. Entities submicroscopically small cannot be described as material as we generally think of it. Quantum-level entities do not interact like billiard balls; instead, they seem to have a quasi-existence in a field of mere potentiality until they are detected; then they become actual. The interaction between them and someone or something else that detects them is essential to their existence. Reality at that level is relational and dynamic.

Whitehead seeks categories of explanation that can apply both to the quantum level of reality and to the world revealed by our unaided senses. In our everyday world it is undeniable that, unless we are asleep or sedated, we are aware of our surroundings and remember our past. So Whitehead posits that subatomic actual occasions are, in a way, aware of their surroundings and of their own past. Whitehead calls them “drops of experience, complex and interdependent”⁽¹⁹⁾ and “occasions of experience.”⁽²⁰⁾ They are examples of what Galen Strawson calls “micropsychism.”⁽²¹⁾ We could call Whitehead’s metaphysics a process panpsychism.

One of the objections to panpsychism is that it seems obvious that some things, those that are not alive, have no sentience whatsoever. So how can we say that everything has a psyche? The answer is that in nonliving things the sentience is confined to the constituent actual occasions, and is not found in aggregations of them. The sentience of living things, in contrast, is a function of their complex and dynamic form, which is more than mere aggregation.

Just as subatomic particles combine to form all the objects of our world, so do actual occasions combine into nonliving and living things. In nonliving things the combinations are simple and stable; in living things they are complex and dynamic. The constituent material of nonliving things does not change over time unless impacted from without. The mentality of nonliving things remains isolated at the subatomic level. Tables, chairs and chunks of rock are certainly not sentient, and process panpsychism does not assert that they are. But living things have a unity of form over time as their constituent material changes. They are not mere aggregations. That complex unity of form over time is accompanied by a complex mentality. The primordial experiences of the actual occasions comprising living things, such as plants, animals and human beings, bind together and reinforce each other, giving birth to a higher-level coherence of experience.

Whitehead’s metaphysics can be seen as a form of dual-aspect monism, but with a twist. Dual-aspect monism, also known as neutral monism, says there is only one type of substance, which has both physical and mental properties.⁽²²⁾ Whitehead agrees, but says reality is better conceived as process than as substance. Every instance of reality, that is, every actual occasion, has both a physical and mental aspect, the physical being how it is detected or experienced by other occasions and the mental being how the world and its own internality appears to itself. The difference between Whitehead’s ontology and dual-aspect monism is that in his view the underlying substrate that has both physical and mental aspects or properties is process, not substance.

There is much more to Whiteheads’ process ontology, but that is enough for now. Let’s return to Kastrup. He is not a big fan of panpsychism because it is only a Type monism and he wants a Token monism. He objects to an ontology that postulates as ontological ultimates a slew of abstract subatomic particles.[p. 11], and the notion that they might in some sense be conscious does not impress him. But there is a way to extend process panpsychism that might be more congenial.

The clue is in a passage from the Bhagavad Gita, Chapter 13, verses 1 and 2. Krishna, The God, speaks to Arjuna, a human:

1 This body is called the ‘field’, and he who knows it is called the ‘knower of the field’ ….
2 Know that I am the ‘knower of the field’ in every field.⁽²³⁾

This passage echoes the earlier Brihadaranyaka Upanishad:

The man who possesses this knowledge becomes the Self of all contingent beings.⁽²⁴⁾

What these texts suggest is that TWE, to use Kastrup’s term, that which experiences, is the same in every experiencer. Not just the same type of thing, but the very same thing (although the term “thing” is misleading, as it is not a thing but that which experiences things). Brahman is the atman (self) that experiences its world in every being. This is a slightly different way to understand what Kastrup is getting at.

Kastrup is after unity. The unity of all that exists can be understood from the inside, as it were. We can say that the mind-at-large is that which is conscious and active in everything, in every event. What appears to be many from the outside, Kastrup’s extrinsic view, is in fact the manifestation of one underlying reality. The mind of each of us is the same as the mind-at-large of all of reality. As I like to put it, there is one universal interiority, which incorporates the interiority of all the separate constituents of reality into one unity of experience, one coherence of interiority.⁽²⁵⁾

The difference between this view and Kastrup’s is subtle but important. We’ve seen that Kastrup, although claiming monism, actually ends up with a dualism: in his view some bodies have mind and some don’t. We can ameliorate Kastrup’s dualism by combining it with process panpsychism, which says that everything has mind, just as everything has body. Everything is composed of occasions of experience, each of which has the dual aspects of interiority (mind) and exteriority (body). And we combine process panpsychism with Advaita Vedanta to conclude that all these occasions of experience are united in one mentality, the mind-at-large. Instead of saying that the mind-at-large thinks of everything so that everything exists within it, we can say that mind-at-large is everything. It is broken into bits, as it were; and the bits, being both mind and body, perceive each other. Each one experiences its world; and its world is the extrinsic view of all the others, which experience their world. The mind-at-large as self (atman) perceives all there is through the senses of each of the bits. And the mind-at-large as body is entirely perceived by those bits that comprise itself.

In other words, to use Kastrup’s terminology, every actual occasion is an alter ego of mind-at-large. If we use the term “God” to mean TWE and say that the mind-at-large is the mind of God, we can say that process panpsychism is process pantheism.⁽²⁶⁾

You’ll notice that I have not gotten to process monism and process pantheism by reasoning from premises to conclusions. Doing so is a fruitless task, as we can see from Kastrup’s attempt. Instead, I have joined some insights and ideas that together form a coherent system of metaphysics. As I have noted elsewhere, we evaluate metaphysics differently from how we evaluate empirical science and logical reasoning. By finding a way to relieve Kastrup of incipient dualism, I believe I have come up with something superior. I hope Kastrup himself would agree.

—

Notes

(1) Kastrup’s website, http://www.bernardokastrup.com, is titled “Bernardo Kastrup’s Metaphysical Speculations.”

(2) Chalmers, “Facing Up to the Problem of Consciousness.” pp. 10-11.

(3) Wikipedia, “Mind–body problem.”

(4) Wikipedia, “Dualism (philosophy of mind).”

(5) Acton, “Idealism.”

(6) Smart, “Indian Philosophy.”

(7) Wikipedia, “Absolute idealism.”

(8) Kastrup, “On why idealism is superior to physicalism and micropsychism,” p. 1. Subsequent references to page numbers in brackets are to this paper.

(9) See, for instance, Shear, Explaining Consciousness, and Dennett, Consciousness Explained.

(10) Wetzel, “Types and Tokens.”

(11) Acton, “Idealism,” p. 112.

(12) Kastrup, “The threat of panpsychism.”

(13) Ibid.

(14) Smart, “Indian Philosophy,” p.156.

(15) Ibid., p. 159.

(16) Chandogya Upanishad III.xiv.1. Zaehner, p. 87.

(17) Chandogya Upanishad IVi.viii.7. Zaehner, p. 109.

(18) Brihadaranyaka Upanishad IV.iv.5. Zaehner, p. 71.

(19) Whitehead, Process and Reality, p. 28.

(20) Whitehead, Adventures of Ideas, p. 221.

(21) Strawson, “Realistic Monism,” p. 25.

(22) Wikipedia, “Mind–body problem,” and Wikipedia, “Double-aspect theory.”

(23) Bhagavad Gita XIII.1-2. Zaehner, p. 303.

(24) Brihadaranyaka Upanishad I.v.20. Zaehner, p. 40.

(25) Meacham, How To Be An Excellent Human, pp. 63-66.

(26) This is a variant of Whitehead’s notion of God. Whitehead has a place for God in his ontology, and his conception is similar this one, but not the same. A comparison of the two is a topic for another time however.

References

Acton, H.B. “Idealism.” The Encyclopedia of Philosophy. Ed. Paul Edwards. New York: Macmillan, 1967. Vol. 4, pp. 110-118.

Chalmers, David. “Facing Up to the Problem of Consciousness.” Explaining Consciousness: The ‘Hard Problem’. Ed. Jonathan Shear. Cambridge Mass. and London: The MIT Press (A Bradford Book), 1997. pp. 9-30. Online publication http://consc.net/papers/facing.html as of 6 July 2016.

Dennett, Daniel C. Consciousness Explained. Boston: Little, Brown and Company Back Bay Books, 1991.

Kastrup, Bernardo. “On why idealism is superior to physicalism and micropsychism.” Online publication https://www.scribd.com/doc/305856953/On-why-idealism-is-superior-to-physicalism-and-micropsychism and https://www.academia.edu/20313118/On_why_Idealism_is_superior_to_Physicalism_and_Micropsychism as of 9 June 2016.

Kastrup, Bernardo. “The threat of panpsychism: a warning.” Online publication https://www.scienceandnonduality.com/the-threat-of-panpsychism-a-warning/ as of 18 June 2016.

Meacham, Bill. How To Be An Excellent Human: Mysticism, Evolutionary Psychology and the Good Life. Austin, TX: Earth Harmony, 2013.

Shear, Jonathan. Explaining Consciousness: The ‘Hard Problem’. Cambridge Mass. and London: The MIT Press (A Bradford Book), 1997.

Smart, Ninian. “Indian Philosophy.” The Encyclopedia of Philosophy. Ed. Paul Edwards. New York: Macmillan, 1967. Vol. 4, pp. 155-169.

Strawson, Galen. “Realistic Monism: Why Physicalism Entails Panpsychism.” Consciousness and its Place in Nature. Ed. Anthony Freeman. Charlottesville VA: Imprint Academia, 2006. pp. 3-31.

Wetzel, Linda. “Types and Tokens.” Stanford Encyclopedia of Philosophy Spring 2014 edition. Ed. Edward Zalta. Online publication http://plato.stanford.edu/archives/spr2014/entries/types-tokens/ as of 11 July 2016.

Whitehead, Alfred North. Adventures of Ideas. New York: The Free Press, 1967.

Whitehead, Alfred North. Process and Reality: An Essay in Cosmology. New York: Harper and Row Harper Torchbook, 1960.

Wikipedia. “Absolute idealism.” Online publication https://en.wikipedia.org/wiki/Absolute_idealism as of 9 July 2016.

Wikipedia. “Double-aspect theory. Online publication https://en.wikipedia.org/wiki/Double-aspect_theory as of 6 July 2016.

Wikipedia. “Dualism (philosophy of mind).” Online publication https://en.wikipedia.org/wiki/Dualism_(philosophy_of_mind) as of 6 July 2016.

Wikipedia. “Mind–body problem.” Online publication https://en.wikipedia.org/wiki/Mind%E2%80%93body_problem as of 6 July 2016.

Zaehner, R.C., tr. Hindu Scriptures. London: J.M. Dent Everyman’s Library, 1966.