by Colin Gunton
Colin Gunton is Lecturer in the Philosophy of Religion at King’s College, University of London, Strand, London, England WC2R 2LS.
The following article appeared in Process Studies, pp. 33-42, Vol. 6, Number 1, Spring, 1976. Process Studies is published quarterly by the Center for Process Studies, 1325 N. College Ave., Claremont, CA 91711. Used by permission. This material was prepared for Religion Online by Ted and Winnie Brock.
Gunton examines Hartshorne’s idealism — his concept that God is dipolar, and that God is the soul of the world.
None of us is wholly the creation of his past, but each creates something new on the basis of what he receives. This statement summarizes an important aspect of the views and teaching of Professor Hartshorne; but, interestingly, it also provides a key to the understanding of his own place in the tradition. Hartshorne is intimately related to a number of recent thinkers, especially, as is well known, to A. N. Whitehead. But he in also a part of the Western tradition of speculative metaphysics that reaches back through Plato to the Presocratics. Its past is his past, and therefore an examination of the relation of the twentieth century process philosopher to three important predecessors will be instructive both for an illustration of the way ideas develop through history and for an understanding of Hartshorne himself. In the following account some simplification is inevitable, as it is with all attempts to look at the history of ideas synoptically. But even simplifications can be illuminating.
I. Idealism: Berkeley Reversed
Each of the three main sections of this paper will begin with a claim of Hartshorne’s and illuminate it with the help of a comparison with a figure in Hartshorne’s past. The first claim concerns his idealism, about which he is explicit. In one early paper he espouses idealism as "the doctrine that psychological categories alone explain the universe" (7:466), while the title of a later article is significant: "The Synthesis of Idealism and Realism" (8). How our philosopher achieves a combination of two apparently opposing doctrines remains to be seen and will emerge as the comparison with Berkeley proceeds.
Bishop Berkeley’s chief popular fame is derived from his theory of perception. In this he takes up his great predecessor’s doctrine that the objects of our thinking, obtained as they are through perception, are ideas. Now, we are not so much concerned here with Berkeley’s narrowing of Locke’s conception as with the kind of language in which his theory is expressed. An idea is something that is "in" the mind. "Since therefore the objects of sense exist only in the mind . . . I choose to mark them by the word idea" (l:xxix). The meaning of in, however, is not very clear in Berkeley. It is beyond doubt that he meant something other than a simple assertion that the mind is a kind of box container into which ideas are conveyed by the senses, although that is the metaphorical background of Lock’s conception of mind as "the yet empty cabinet" (9:I, II, 15). One suggestion is that the "in is the equivalent of in relation to" (10:286), but in reply to this is I. C. Tipton’s view that Berkeley is more ambiguous than his defenders allow (12:93-95). It is therefore a complex and difficult matter of interpretation, by contrast with which the view of Hartshorne is somewhat more straightforward. "The vaunted transcendence, taken as externality of known to knower, is . . . really a defect of our human knowledge." It is when philosophers do not take account of our finitude that they can hold "the view that mind does not literally include its objects" (DR 111).
Hartshorne’s view that in perception the mind includes its objects does not entail that he is being crude or less subtle than Berkeley. Rather, he is working in a different direction and with a particular theological model in the background. For him, the paradigm case of perception, against which all other instances are to be judged, is that of God. Only God is omniscient, and for him alone there is nothing "outside." This is, of course, what is meant by panentheism: not that God is in everything -- though in a secondary sense he is -- but that the primary relation of God to other things is that all things have their becoming in the omniscient mind of God. In him they live and move and have their being (PSG 22).
But our inquiry is in danger of running ahead of itself. The nature of the inclusiveness will occupy our attention later; in the meantime we have to ask what precisely it is that is contained in the mind of God and in the minds of other things and how it gets there. Here the contrast with Berkeley marks Hartshorne’s essential difference from, and development of, the great idealist. How do ideas enter the minds with which Berkeley is concerned? Certainly, they have to be placed there, because we ourselves are not responsible for them.
Philonous. . . . doth it . . . depend on your will, that in looking on this flower, you perceive white rather than any other color? On directing your open eyes towards yonder part of the heaven, can you avoid seeing the sun? Or is light and darkness the effect of your volition?
Hylas. No, certainly.
Philonous. You are in these respects altogether passive. (2:228)
If we are passive in perception, whence our ideas? The heart of Berkeley’s apologetic for theism beats in the twofold answer to the question. First, there is nothing about the ideas themselves that could account for their being as they are. They are totally inanimate and inactive, and it is sheer nonsense to suggest that they should initiate our perception; "how can that which is inactive be a cause; or that which is unthinking be a cause of thought?" (2:250). Second, therefore, such ideas as are not accountable for in terms of the agency of finite minds must be accounted for theologically. They derive from the one infinite mind, God’s: "there is a mind which affects me at every moment with all the sensible impressions I receive. And from the variety, order, and manner of these, I conclude the author of them to be wise, powerful and good, beyond comprehension" (2:249).
Hartshorne agrees in the basic idealism, that all reality is in some way related to mind. He agrees in seeing the mind as a receiver of the objects of perception: like Berkeley’s his is a causal theory. Where he disagrees is in his rejection of the two central points of Berkeley’s theory that have just been described. In doing so, he shifts the initiative for perception’s causation from God to the individual object, or cosmic event, to see it in his terms. Far from being nonsense that the object of perception should cause us to see it, it is a major feature of Hartshorne’s world-view. Objects of perception are not inanimate ideas but real events (hence the "realism"). Reality consists of events that are all animate to a degree appropriate to their complexity and organization. Hartshorne, as he often says, is a panpsychist. His doctrine holds that everything is creative, producing something that did not exist before it; and it is these creative events that are the causes of other, later events perceiving them as they pass into the past (RSP 134f).
God has an essential part to play in all this, but inevitably it is very different from the function ascribed to him by Berkeley. In the latter, God is essentially an active being, as is clear from the passages quoted above, while other beings are passive, at least insofar as they are related to God. It is a very voluntaristic conception of God, a God who is pure will, and therefore in this respect nearer to the classical concept of God than to Hartshorne’s. It is he who causes passive minds to perceive; how, otherwise, could inanimate ideas enter mental realities?
Hartshorne’s God, on the other hand, is not conceived in terms of his difference from other realities in the world; the concept is true to Whitehead’s principle that God should be the supreme instantiation of and not the exception to metaphysical principles (PR 521). Just as finite events receive some of their reality from the predecessors they perceive, so it is with God. Like them, and therefore also like Berkeley’s finite perceivers, he is passive in perception; with them, the content of his perception is independent of his will, for the creative events are free -- though, of course, within the limits that God also represents -- to give to reality and so to God something of their creative novelty. God’s function in relation to other beings is therefore rather of persuasion than of voluntaristic initiation. "God changes us by changing himself in response to our previous responses to him, and to this divine response to our response we subsequently respond. Creation is modeled in dialogue" (CSPM 277). Precisely how this is conceived to take place does not concern us here. For our purposes, the point is, in summary, that Hartshorne shares Berkeley’s idealism, for all reality is to be understood in terms of mind. But the idealism is transformed. Reality is not ideal simply in being mind-related. It is ideal in that every event -- and that means all reality -- has a mental component. Therefore, through its initiative, it really impinges upon the events that are related to it in the spacetime continuum. The present event perceives the events immediately in its past realty, as they are, and as they pass into the cosmic memory. The transformation is brought about by applying Berkeley’s concept of the perceiving mind also to God -- and at the same time by transferring the initiative in the mind-object relation from God alone to the individual event in dialogue with God.
II. Neoclassical Theism: Aquinas Upended
Hartshorne’s assertion that his theology is neoclassical is his second major claim to be considered here. In this, his relationship to Aquinas is important, since the medieval scholastic theologian represents classical theism in its most perfect form. As any reader will know, much of Hartshorne’s writing is concerned with sparring with the classical concept. Indeed, it is not a great exaggeration to say that the battle is a constant preoccupation. But this only serves to emphasize the importance of the relation to the figure in the past. Men do not attack those they think to be unworthy of notice or beneath contempt. Moreover, the very name, neoclassical, is significant. Different emphases of Hartshorne’s theology will come to light when different parts of the word are stressed. Neoclassical theism is new, but it is new in relation to the classical tradition.
Hartshorne takes from Aquinas his realist view of perception. When an event of perception takes place, the perceiver is really related to the object of perception and is therefore internally related to it. Moreover -- and it is here that Hartshorne is unequivocally opposed to some idealistic theories -- the object perceived is externally related to the perceiver since he, qua perceiver, is passively receptive and in no way affects its reality. "Aquinas . . . makes a fine contribution to the theory of ‘external’ and ‘internal’ relations, to use language current recently. The Thomistic language is perhaps better: that relations are either ‘real’ or merely ‘logical’" (PSG 119f). In fact, all is well until Aquinas comes to deal with the relation of God to the world, when, like Berkeley, he refuses to see God in the same way as the rest of reality. If the perceiver is really related to, and so affected by, his relation to what he perceives, God, as the supremely relative being, the omniscient perceiver, will be the most affected of all. Aquinas has made the mistake of inverting the relation: "the divine knowing is creative and hence not at all the same thing as human knowing . . . Thomas thinks it has, however, an analogically common meaning. But it is an analogy which inverts the two terms, giving the ‘subject’ the very role taken, in the ordinary case, by the object!" (PSG 120). "Does this not imply that God, so conceived, is a super-object rather than a super-subject?" (PSG 131). Where, in the standard case, the subject is internally related to the object of perception, with God it is the reverse: the subject (God) is externally related, so that his perception of the world makes no difference at all to him. But that is a logical absurdity.
Why is it so important for Hartshorne to point out the source and nature of the error? First of all, it is because he believes that by making a logical blunder Aquinas has produced a false concept of God. But, second, Hartshorne wants to show that a true concept of God can be derived from philosophizing within the same tradition of thought. What is here meant by the "same tradition of thought" requires some clarification. The neoclassical theologian believes that Thomas has not only a distorted concept of God but also a false ontology. Where the two are in the same tradition is in their sharing what can be called a cosmological approach to metaphysics: both derive their concept of God from reflection upon the cosmos. To put it otherwise, both produce a concept of God by arguing from the world to God by means of analogy. Aquinas begins in the right place, but his analogical reasoning is false. God is treated as the exception to metaphysical principles, with the result that his relation to the world is fundamentally misconstrued. Because he is unrelated to the world, and as a result unaffected by its relation to him, he is the unloving, impassible, absolute, timeless unmoved mover and, one might add, the negation rather than the affirmation of our life on earth.
That this distorted view of God is closely related to the inversion of the perceptual relation is clear when we realize that all the attributes of the classical deity follow from the assertion of God’s absoluteness. For Hartshorne absolute is a technical philosophical term, whose meaning he takes from Aquinas. It is only secondarily to be understood in its meaning of an absolute ruler, with all the unfortunate implications that has for man’s relation to God. Primarily, it is a synonym for externally related: the absolute is the term of a perceptual relation that denotes total unaffectedness by the relation, just as the number three or the Form of the Good or the tree in the quad are unmoved by my conceiving or perceiving them (DR 67-74).
If God is conceived as absolute in relation to the creatures, as we have seen that he is according to Aquinas, then all the gloomy negatives of the classical concept follow logically and necessarily from the primary insight. Hartshorne will have nothing to do with this abstractly negative God, and it is one of the achievements of his philosophy continually to have pointed out the implications of classical theism (even though, of course, classical theists would wish to resist the drawing of some of them). Perhaps, however, it is more accurate to say that he will only deal with the negative abstractions if they are firmly subordinated to other conceptions; if the language of classical theism is turned firmly upon its head. Two things happen in Hartshorne’s positive doctrine. First, he uses the same language, but negates the negatives. God is not absolute, but relative, because, as omniscient, he perceives all those events that cause him to perceive them; not unmoved and impassible, but very moved, sharing all the joys and sorrows of the creatures; not timeless, but participating temporally in all that happens.
The other major process theologian, A. N. Whitehead, found it needful to create a whole new language for his ideas. Hartshorne has expressed a similar philosophy very much in traditional Aristotelian terms, for example in his use of the language of perceptual relatedness for Whitehead’s prehension. Hartshorne’s achievement is the less original, for the creator of new language, so long as he is not using barbarisms or neologisms for the sake of it, is the one who enables language to do more in its quest to grasp symbolically the universe in which we do our thinking. Hartshorne’s merit is a lesser one, but important for all that: he shows us how neoclassical metaphysics is anchored in the great philosophers of the past and thus allows us to evaluate the present philosophy more easily.
This brings us to the second consequence of the inversion of the original Aristotelian language. As is well known, Hartshorne’s God is dipolar. We have so far described the concrete pole of God, God as he is in his direct relatedness to all other reality. But that is not all that has to be said about him. After all, God is not merely relative: his is a supreme relativity, embracing all else that happens; he is not merely temporal, but his reality stretches infinitely back in time and will continue to eternity. There is an abstract pole, too. Abstractly considered, God is absolute, for his relativity is absolute and unsurpassable; he is immutable, for his mutability cannot waver, and soon (MVG, ch. I; CSPM, ch. VI). All of Thomas’s abstract terms are used, but not in the sense in which he used them. They describe the abstract pole of the concretely relative God (PSG 507f). Indeed, cannot the scholastic’s chief error be characterized by saying that he has made the whole what should only be a part, and a subordinate part at that?
And so the relationship between Hartshorne and Aquinas is not unfairly described, in the words of the old cliché, as one of love-hate. It might be said, without exaggeration, that the former has played the same game, but with very different rules; or rather, according to his own account, that he has played the same game but has shown that Aquinas did not keep the rules at all. The first version would be fairer to Aquinas, for it is unlikely that he would find Hartshorne’s charge convincing. He was operating with a negative theology, while Hartshorne’s is a theology of eminence. They are in different worlds of thought: the one sees the thing or substance as the ultimate reality, the other the event. All follows from that. Therefore Hartshorne might seem to be a little hard on Aquinas when he accuses him of mistaking the facts of perception. Thomas had his reasons for seeing God as an exception, for he was operating with a very different set of axioms. But, for our purpose, the interesting feature to note is that the worlds of the two, though different, are in a dialectical relation to each other. Negation is not simply negation, but negation with a view to taking the negated concept up into a higher synthesis.
III. The World-Soul: Spinoza Transformed
The third claim of Hartshorne’s that we shall examine is that God is the soul of the world (MVG, ch. V). Once again, we shall find him in a dialectical relationship with a predecessor, though not one that fits the Hegelian pattern as does that with Aquinas. First we must examine briefly what he says about Spinoza. His word of praise is that the great rationalist performed a notable service in carrying through the logic of the classical conception, thus revealing it in its true colors (PSG 189-91). Spinoza is still numbered among the unconverted, but there are signs that light is dawning. By taking the physical world up into God he at least went some way to seeing a real reciprocal relationship between God and the creatures. "We wish only that Spinoza had dared further and had treated temporal extension according to the same logic. We endure through limited time God endures though unlimited time. . . . But had Spinoza done this, he would have been a panentheist rather than a pantheist. We must take him as the pantheist which he is" (PSG 191).
If we probe a little deeper, we shall find that there is much more to be said about their relationship. Spinoza is often thought to be the most abstract of thinkers, the one most successful in expelling figurative and metaphorical concepts from his system. Thus Stuart Hampshire attributes to him the liberation of theology from gross pictures (6:40f). And yet, paradoxically, that same commentator speaks, somewhat dismissively, of metaphysical systems like Spinoza’s as depending on the generalizing of metaphors ("logical doctrines and linguistic analogies" -- 6 :218f). This is a far more fruitful suggestion, for it is in their metaphorical background that we shall best view the relationship between the neoclassical panentheist and the classical pantheist.
God -- or substance, or nature, or the universe, however we wish to put it -- is, for Spinoza, comprehended by the human mind under two of his attributes, thought and extension. God is infinite thought and infinite extension (10: II, PROPS. 1-2). Whence did Spinoza derive those concepts? Not from pure thought alone, surely. If we glance back a few years to the speculations of Rene Descartes, we shall see that for him thought and extension were the two realities comprising the human person. Descartes metaphysics -- his view of what was real -- derived from reflection on the fundamental discovery that he, Descartes, was "precisely speaking, only a thinking thing, that is, a mind (mens sive animus), understanding or reason" (4:88). Thus he was "a substance whose whole essence or nature consists only in thinking, and which, that it may exist, has need of no place, nor is dependent on any material thing" (3:27). That is to say, Descartes’ view of the world began with his reflections on the non-extendedness of mind and proceeded to contrast it with matter, of which his body consisted, whose essence was extension. The whole of reality is conceived after the pattern of either mind or body. When Spinoza took over the two key terms, and made them to coalesce into one single reality with two aspects, can it be supposed that the original metaphor was completely lost? Rather, it would seem that Spinoza’s generalized metaphor is that of the mind and body, though, of course, he conceives the relation of thought and extension very differently from Descartes.
The Spinozist substance, Deus sive natura, is then a kind of infinite mind-body (mens sive corpus). But that, of course, is true also of the conception of the world to be found in the philosophy of Charles Hartshorne: "we shall never understand a God of love unless we conceive him as the all-sensitive mind of the world-body" (BH 208). There are, needless to say, great differences in the understanding of the analogy, but let us first glance briefly at some of the features the two have in common. In particular, there is present in both the desire to solve the problem of the relation of mind and body by denying that there is an essential difference between the two. Ever since the problem was set in its starkest form by Descartes, there have been various attempts to wrestle with the question he bequeathed. Over the years these have ranged from attempts to uphold something like a Cartesian position, to theories which deny the ultimate reality of either mind or matter. Hartshorne’s wish to be both idealist and realist is again revealed in his doctrine that everything is both "mental" and "physical." In this sense, he shares the concern of Spinoza.
Where he differs is in the way he achieves his synthesis. For him ultimate realities are not things, but events. "Substance is a ‘being’ to which adventures happen, or experiences. . . . . The alternative . . . is to view events or states (e.g., ‘I now’) as the concrete realities, and construe enduring things, substances, persons, as ways in which events are qualified, and related to other events" (CSPM 45f). What we take to be things are in fact composed of myriad events, linked together in both space and time in various groupings at different levels of complexity. Each event is a momentary mind-body understood on the analogy of the organism. "We must choose between a dualism and an organic monism" (LP 191f), Hartshorne argues and proceeds to show how it is possible to understand both reality as a whole and its parts to be organic (LP 191-215). Thus the panpsychism we mentioned in section I above must be further specified. it is not a panpsychism of Cartesian souls extended in time but not in space. Everything for Hartshorne is both spatial and temporal, or it would not be at all. From the lowest electronic event to the highest most complex cosmic becoming (God’s) there are found elements of what we call matter and mind. Our frequent mistake is to abstract one from the other, and in our everyday language and metaphysical thinking to misconstrue the nature of reality.
The temporality of every reality brings a contrast with Spinoza’s system, for which time is fundamentally unreal. The infinite mind-body is not for Hartshorne a static whole "thing" whose apparent changes and movements are merely rearrangements of an unchanging totality; rather, each event is real, new, unique and, moreover, contributes cumulatively to the reality that has gone before. When we ask, then, in what sense Hartshorne’s God is the soul of the universe, the answer is that God is the soul-event in which is summed up all past and present reality. God is the divine cosmic happening that embraces all other past and contemporary happenings. He is the whole universe as it happens, on the basis of its remembered (by God) past at any given moment in the universal process, and he is more than that.
The relationship of God to the world is, therefore, an inclusive one, to be understood on the analogy of the case we know directly, our own. According to the neoclassical understanding, the human mind-body is a series of events organized into a particular finite chain. Some of the events that impinge upon our minds are internal to ourselves -- pain, memory, etc -- while others are external, as when we perceive other series of events going on about us. With God, there is no such distinction. Everything is directly and omnisciently perceived because everything is both internal to him and consciously observed (MVG 177-92). The world could therefore be defined as what happens within God; and God as the soul of the world which is his body.
I have suggested elsewhere that Hartshorne’s cosmos is what happens when Spinoza’s God is catapulted into time (5:93). But it should be stressed that to make the timeless temporal is something of a transformation. In particular, it is to make possible a distinction between God and the world. Whereas in Spinoza God is the world, with Hartshorne there is, as was observed near the beginning of this paper, panentheism rather than a pantheism. Sometimes this cosmos appears to be little more than a pantheism in motion, as when Hartshorne says rather cryptically that "God is the self-identical individuality of the world somewhat as a man is the self-identical individuality of his ever changing system of atoms" (MVG 230f). But from another point of view it is possible to stress the distinction between God and the world. How near we are to pantheism is not easy to discover and is in any case outside the limits of this study. Suffice it to say that when we think of God as the contemporary cosmic event -- stressing his relative pole -- the system seems rather pantheistic; but when we stress the abstract pole, and conceive of God in his function as the cosmic memory and container of the past, the distinction comes into greater relief. As always with this philosopher, it is necessary to keep both aspects in view.
As a concluding summary, we can say that Hartshorne shares Spinoza’s predilection for the mind-body metaphor, and, moreover, his fundamental rationalism: the belief, that is, that it is possible to describe the universe as a whole by means of philosophical concepts. The difference is revealed in the use that is made of the metaphor and the way in which the words mind and body are understood. The universe is conceived to be essentially temporal in its deepest reality and to be internal to God rather than to be God.
A philosopher’s relation to his past is always important, because ideas do not just happen in an intellectual vacuum. Whatever the merits of Hartshorne’s speculation for an understanding of the universe, he has thrown light on the way that human thought moves and develops. His relation to the three great metaphysicians we have treated -- and it is possible that treatment in the light of others would also be illuminating -- is by no means uniform, His relation to Berkeley has to be teased out, for the British idealist is not often mentioned by the neoclassical metaphysician. But, nonetheless, he does provide an interesting backcloth to some of the elements of Hartshorne’s view of the relation of man and God to the world. The relationship to Spinoza is also elusive, for mention of him is made chiefly in the context of a discussion of classical pantheism, neither of whose leading ideas is accepted by Hartshorne. The chief hint we are given of a relationship is the clear feeling that Spinoza might have looked at other possibilities opened up by his speculation.
In Hartshorne’s relations to both of these predecessors there are elements of rejection, influence, and development. But his dominating concern in his relations with the past is to overturn the classical concept of God. This means that Aquinas’s Aristotelianism is never far from his thoughts and writings. The pattern, however, is almost classically Hegelian: if Aquinas is the thesis (the absolute), Hartshorne is the antithesis (the relative) and the resulting synthesis (dipolarity of relative and absolute)
Thus the relationship with the past is an eclectic one. Different parts of the metaphysical inheritance have been combined in an original way to produce a view of the world that is Hartshorne’s alone, for even those who follow him will have alterations to make. Undoubtedly they will if they are true to his doctrine that there must be an element of freedom in the way a present creative event uses its past.
BH -- Beyond Humanism: Essays in the Philosophy of Nature. Chicago: Willet, Clark & Company, 1937. Nebraska: Bison Books edition, 1968.
CSPM -- Creative Synthesis and Philosophic Method. London: SCM Press, 1970. LaSalle: Open Court, 1970.
DR -- The Divine Relativity: A Social Conception of God. New Haven: Yale University Press, 1948.
LP -- The Logic of Perfection and Other Essays in Neoclassical Metaphysics. LaSalle: Open Court, 1962.
MVG -- Man’s Vision of God and the Logic of Theism. Chicago: Willett, Clark & Company, 1941. Reprinted, 1964, by Archon Books, Hamden, Conn.
PSG -- Philosophers Speak of God (with William L. Reese). Chicago: The University of Chicago Press, 1953.
RSP -- Reality as Social Process: Studies in Metaphysics and Religion. Glencoe: The Free Press, and Boston: Beacon Press, 1953. Reprinted by Hafner, 1971.
1. G. Berkeley, Principles of Human Knowledge.
2. G. Berkeley, Three Dialogues between Hylas and Philonous. London: Dent, 1910. -
3. R. Descartes, Discourse on Method. London: Dent, 1912.
4. R. Descartes, Meditations on the First Philosophy. London: Dent, 1912.
5. Colin Gunton, "The Knowledge of God According to two Process Theologians," Religious Studies, 11/1 (March, 1975), 87-96 (abstracted in PS 5:144 f).
6. S. Hampshire, Spinoza. Harmondsworth: Penguin Books, 1962.
7. C. Hartshorne, "Contingency and the New Era in Metaphysics," Journal of Philosophy, 29 (1932) 421-31, 457-69.
8. C. Hartshorne, "The Synthesis of Idealism and Realism" Theoria (Sweden), 15 (March 12,1949), 90-107.
9. J. Locke, An Essay Concerning Human Understanding.
10. A. A. Luce, "Berkeley’s Existence in the Mind," Locke and Berkeley, C. B. Martin and D. M. Armstrong, ed. London: Macmillan, 1968.
11. B. Spinoza, Ethics.
12. I. C. Tipton, Berkeley: The Philosophy of Immaterialism. London: Methuen, 1974.