Leibniz propounds a pluralistic metaphysical idealism by reducing the reality of the universe to centres of force, which are all ultimately spiritual in their nature. Every centre of force is a substance, an individual, and is different from other centres of force. Such centres of force, Leibniz calls monads. These forces are unextended, not subject to division in space. None, excepting, of course, God, can destroy these monads, and so they are considered to be immortal in essence. Though quantitatively, the monads are practically similar to one another, qualitatively they are different. As the monads are spiritual entities, their internal differences too are determined by a spiritual character. It is this difference among them that gives them their distinctive individuality. We are reminded here of the viseshas, or differentia, of the ultimate atoms in the Nyaya and Vaiseshika philosophies, the viseshas giving a distinctive individuality to the atoms. The monads of Leibniz are subject to the changes of perception and appetition, each monad striving to attain clearer and clearer perception, which process is an attempt of the monad to come to a consciousness of greater and greater perfection in itself. The manifoldness of the monads and the way in which they are arranged account for the diversities of the world. These monads are present everywhere in the universe – in man, animal, plant and even in inanimate matter. For Leibniz there is no dead matter or blind force. Matter is endowed with life through and through. As all monads are not of the same kind, they admit of a hierarchy of degrees among themselves. There is a rise in the consciousness of perfection from matter to man. In matter the monads are unconscious; in man they rise to reflective consciousness.
Every monad is like a mirror, which reflects in itself the entire universe. A universal situation can be seen represented in a monad. The degrees of clarity in which the monads reflect the universe in themselves differ according to the position which they occupy in the great hierarchy, which, again, is determined by the degree of the clarity of their perception. Their positions are determined by the intensity and clearness of their consciousness. The higher ones are considered to be the images of God, and the lower ones mirrors of the universe. Though the monads have this capacity, they are by no means infinite, for outside them there are other monads. Leibniz tells us that the past, present and future of things can be seen in a single monad; the knowledge of the constitution of a monad would give us a knowledge of the whole universe. In the hierarchy of monads there are infinite degrees, from the lowest to the highest, a gradually ascending series of spiritual entities or forces with no jumps or leaps of any kind between one monad and another. God is the highest Monad. Leibniz proves the existence of God in five ways: by the ontological proof, the cosmological proof in terms of the law of sufficient reason, the teleological proof, proof by the law of pre-established harmony, and the epistemological proof which requires a background for the eternal necessary truths seen in the world.
Like the entelechies of Aristotle, the monads of Leibniz are directed by an inner necessity, and not by outward compulsion. It is to be remembered that these monads are windowless essences, not permitting in the entrance of anything from outside. One monad cannot influence the other. True knowledge is infinite, unfolded from within, not received from outside. The possibilities of a monad are hidden in it, as a tree is latent in a seed. Evolution is the process of the realisation of the inner potentialities of the monads. The higher stages of evolution include and transcend the lower ones. The whole life of a monad is therefore a long chain with many links of the stages of self-transcendence. The past is over-stepped in the present and the present transcended in the future. We have again the reminiscences of Aristotle in the view of Leibniz that the succeeding stages in the evolution of a monad are the results or effects of its preceding stages, so that no action from above or outside is necessary for its evolution. Though one monad is different from the other, each monad bears a harmonious relation to all the other monads. We may notice here the germs of the philosophy of organism brilliantly expounded later by Whitehead. Leibniz tries to bring about a reconciliation between mechanism and teleology by holding that insofar as the physical realm is governed by strict law and order, it can be explained mechanically, but that the scheme of the universe is directed by a final aim towards which it evolves. Mechanics, for Leibniz, is rooted in metaphysics; the mathematical and mechanical laws of the physical realm point to God as their ultimate goal. Science and religion are thus brought together. We get an organic whole of a universe where every fact or event had a reason why it exists or happens in such and such a manner, in such a place and at such a time. Not only should every judgment have a reason to prove it, but every object a reason to be. This is the law of sufficient reason advocated by Leibniz, which is at once logical as well as metaphysical. This law leads to a kind of determinism rather than to give room to free-will, for the causes of an event or a fact are determined already by the circumstances in which a monad is placed in the hierarchy, and even an apparent free choice would only be the result of the joint action of the various conditions, the contingent past and present factors, which make the monad what it is. But Leibniz allows some free-will without properly explaining how this is to be reconciled with the absolute supremacy and omnipotence of God. The law of sufficient reason requires the universe to be a rational whole, where logical and metaphysical truths become identical.
The individual souls which form a divine hierarchy of monads have much in common with God who is their prototype. The reason in man is essentially one with God's consciousness, but it differs from the latter in the degree of its intensity. The kingdom of God has therefore two aspects: the hierarchy of monads and the physical universe. All these work together parallelly by pre-established harmony. The same old parallelism in the workings of the mind and the body persists with a different note in the philosophy of Leibniz. God, according to Leibniz, has arranged the mind and the body in such a way that the two work in harmony with each other. God has endowed all monads with identical contents. The theory of windowless monads prevents any interaction among them. The harmony of functions between the psychic and the physical states is pre-established by God, in the beginning. Though the monads have different kinds of perception, there is a single current underlying them all. Minds and bodies form parts of the organism of the universe. Though the parts of the organism are connected by causal relations, it should not be forgotten that these relations are strictly preordained by God and are not to be understood in the sense of actual interaction.
There is a difference in the manner of action in souls and bodies. Souls are directed by a teleological law; bodies are determined by mechanical motion. But both work in unison by pre-established harmony. Leibniz also adds that the spiritual monads, when they are perceived by the senses, appear as the phenomenal universe; in other words, matter is spirit discerned by the senses.
God, Who is the highest Monad, is changeless and has no modification. He is the absolutely real being. But the great importance which Leibniz gives to logic and mathematics, considering them to be examples of eternal truths, makes him think that the laws of human thought are binding on God, also.
Leibniz holds that there are monads within monads. There are organisms living even in what is ordinarily supposed to be dead matter. Every particle of matter houses several living organisms. Every such organism, again, is an abode of several other organisms, and so on. His theory of the universal presence of living beings is called panpsychism.
The relation between God and the monads Leibniz speaks of in different ways. Sometimes he thinks that they are eternal, sometimes that they are created by God, Who can even destroy them, if He wills, and sometimes that they are manifestations of God Himself. If they are eternal, they must be different from God and have nothing to do with God, in which case they cannot reach the perfection of God. Further, as they are limited entities, they cannot be eternal. If they are not eternal, they must be perishable and have no real worth in them. If their goal is God, God must be immanent in them; in other words, they must be God Himself appearing, and not entities created by God Who can even destroy them. The monads are either existent or non-existent. If they are existent, they are real, and so cannot be destroyed; if they are non-existent, there is nothing to be destroyed.
The plurality of monads in the system of Leibniz is a great hindrance to a satisfactory explanation of their relation to God. If they are really plural in their essence, they will become independent eternal entities, whose eternity would only be in name. For, there cannot be eternity of many things; individuality is subject to spatiality, and so to change. Leibniz is anxious to make the universe a harmonious whole, but this he does with a highly artificial scheme of pre-established harmony. This pre-establishment cannot be established without the doctrine of the plurality of monads, which, again, cannot be established without pre-established harmony. The reasoning becomes circular. That there is interaction between mind and body and between individuals cannot be doubted. Much later, Whitehead made it clear that every entity in the universe flows into every other and that there are no watertight compartments among things. Moreover, if the monads are different from one another, they would have to be contained in space, for we cannot have the notion of difference without the notion of space. But for Leibniz the monads are immaterial and unextended. If they are extended in space, they are material bodies; if they are unextended and spiritual, there cannot be a plurality of them. Only a universal, undivided wholeness, where plurality is transcended, can justify the spirituality of the monads. Else, they would be reduced to physical atoms hanging in space.
In the philosophy of the Vedanta, the plurality of ultimate substances has no place. It admits that there is a plurality of Jivas, or individual souls, but these are not the ultimate essences of existence. The essence of the Jiva is the Atman, which is pure consciousness in nature. There is no plurality of Atmans; the Atman is one in reality and it is identical with God, or the Absolute. We notice a confusion in Leibniz between minds and souls. The Vedanta makes a distinction between the mind and the soul. The soul, in the sense of Jiva, is a manifestation of the Supreme Atman through the medium of the mind. The mind is as much physical as the body, though much subtler and more transparent than the latter. In this sense there can be a plurality of individual souls, but not of ultimate essences or realities. A plurality of realities would make the realities individual beings and consequently transient in nature. If the monads of Leibniz are distinguishable individualities, they cannot be eternal and immortal. If Leibniz means by his monads minds and not spiritual essences in the sense of the Atman, the Vedanta would agree with Leibniz that the monads are many. But as ultimate realities they cannot be so, for reality can only be one. Plurality is impossible without spatiality, and reality is above space.
Leibniz seems to think that the monads may even be destroyed by God. This is a great self-contradictory view held by him, for what is subject to destruction cannot be immortal; immortality implies eternal existence. What is eternal cannot be an effect or product of something else. Eternity does not begin somewhere in time. Naturally, the uncreated which should, at the same time, be non-spatial, has to be identified with the ultimate reality, which is God. Destruction in the sense of transformation of state may be brought about by God in regard to phenomenal objects, but not immortal beings like the monads of Leibniz. The Jivas, on the other hand, are essentially indestructible beings, though their relative constitutions may undergo change in the process of evolution. Even here it is the psychic or mental body which constitutes the Jivahood that undergoes the change; for its essence, which is the Atman, is beyond all change. When it is said that the Jivas undergo the process of change in evolution, it must be remembered that only the factors that constitute Jivahood, or individuality, undergo change and not the basis of Jivahood, which is the Atman. Hence, for the Vedanta, there is the evolution of relative Jivas but not of ultimate realities. Even a miracle cannot destroy the ultimate essence of things.
It is very difficult for Leibniz to uphold the theory of an organic universe with the supposition that the monads, which are the ultimate essences of things, are individualities separate from one another. How can there be organic relation among entities which are windowless and do not admit of any relation? Yet, Leibniz attempts such a theory by making the monads mirrors reflecting one another. How can we conceive of reflection without relation? Leibniz merely seems to substitute the word reflection for interaction, for what is reflection if not action of one on the other? In the philosophy of the Vedanta, however, the organic unity of the universe is maintained by the admission of individuals which influence one another, not in the sense of causality in a space-time realm, but as universal influence exercised by one on others. In other words, every individual in the universe influences and bears relations to all others, which, again, influence and bear relations to it. In its theory of the phenomenal universe of individuals, the Vedanta is not far from Whitehead who propounds the philosophy of a perfectly organised universe of entities, which flow into one another to form a connected whole, ceasing to be individualities themselves. The monadology of Leibniz is applicable to the Vedanta philosophy of the relative universe of phenomenal individualities, but not to its theory of ultimate reality.
As for Leibniz, so for the Vedanta, there is no vacuum in the universe uninhabited by individuals. For both there is no dead matter, all matter is instinct with life, though it may not be perceptible to the senses. However, for the Vedanta, the individuals that fill the universe are not windowless entities, but influence one another tremendously. In an organic universe there cannot be uninfluenced bodies, for, if anything remains unaffected, it would detract from the organic character of the universe. The Jivas, in the Vedanta, do mirror the universe in themselves, but not as windowless substances disallowing interaction. The universe is a family of members which bear among themselves a relation of equality in essence and mutual harmonising and balancing of forces. To the Vedanta, the whole universe is filled not merely with minds but by the Universal Self, which is indivisible consciousness. Though the monads of Leibniz are said to be spiritual in nature, he appears to be contented with merely rising to the mental level and attributing to them as their essence what the Vedanta would call mind, and not consciousness. We should not identify mind with the spiritual consciousness, for the former is subject to change and modification, it functions in a space-time world and it forms the individuality of a being; while the latter transcends individuality and exists as the common essence and reality underlying all individualities.
Leibniz holds that the monads are moved by an inner necessity and not by outward action. We have in the philosophy of the Vedanta a grand synthesis of the subjective and the objective approaches, where inner necessity and outward compulsion mean the same thing. By inner necessity we have to understand the supreme law of the Absolute which works from within as the Self of all things, but which also acts from without on account of its omnipresence. The individual is not really cut off from the external universe; the universe is its own outward environment. As there is only one Self in the universe, it cannot be confined to any particular individual to act as an inner necessity as distinguished from outward impulsion. The one Absolute is felt inside and outside with equal force as necessity as well as compulsion. To the Vedanta, Ishvara is the one reality of the universe and the individuals are not really different from Him. Obviously, therefore, he should act in a universal manner and not as restricted to any particular individual. The difference between internality and externality arises on account of a defect in individual perception, which always works on the basis of the false notion that the subject of perception is different from the objects perceived outside. Individual action and cosmic law, free-will and universal determination, effort and grace must be one and the same in a unitary universe grounded on the Absolute Self.
The Vedanta would agree with Leibniz that there are no leaps or jumps in the arrangement of the individual souls in the universe. Everything is organically connected with everything else. There is nothing private, secret or hidden anywhere in the universe. All thoughts and actions are at once made public, a property of the universe the moment they arise or take place. Selfishness is, therefore, an illusion which has no meaning whatsoever. The good of the individual ought to be necessarily the good of the universe, and if any individual attempts in ignorance for what it thinks to be its own private good, it shall be defeated in its attempt. Every action receives a reaction from the universe outside; the universe ever maintains its equilibrium and never permits a disturbance from any of its parts. In this theory, however, the Vedanta rests on its doctrine of the Absolute as the sole reality of the universe, which is the reason why there is an organic unity among individuals. Without the Absolute Self there can be neither an explanation of an organic unity nor even its existence. It is because of the existence of the Absolute that an individual is capable of representing a universal situation in any given condition of its phenomenal existence.
There is, in the philosophy of the Vedanta, too, a hierarchy of degrees of perception and position among the individual souls. But this hierarchy is purely relative, valid only in the changing universe. Here, we have to remember that by the word `universe' the Vedanta means not merely the visible physical phenomena but also the subtle and the causal backgrounds of these phenomena, ranging beyond sense-perception. The hierarchy of souls begins with the body of Virat and ends in Ishvara, Who is the supreme cause of the universe. Here, again, we have to add a note that this hierarchy is not of ultimate realities but of phenomenal individualities. The individuals form a graded series of greater and greater approximations to Perfection as they are situated nearer and nearer to the consciousness of the Absolute. Every higher individual soul, on account of its greater approximation to the Absolute, transcends all lower ones in knowledge, power and in every aspect of being.
The Vedanta does not formulate two universal governments: the teleological hierarchy of souls and the mechanistic phenomena of the physical universe. For it these two aspects of the universe are not independent of each other but form two phases or appearances of one connected whole. Even according to the view of Leibniz himself, matter is spirit itself sensuously perceived. On this supposition there is no need for two kinds of governments,—it is the one law of God that works in the same way both in the physical and psychic universe. What is applicable to bodies is applicable also to minds, though the former on account of their being contained in the realm of space-time appear to be governed by the laws of mechanics and do not seem to give any hint of a design or purpose in their motions. The realms of mechanism and purpose appear to present themselves as different from each other on account of a serious defect in the ways of our perceptions, viz., the separation of space-time phenomena from the mental ones, in spite of the fact that bodies are expressions of minds. The psychic universe has two aspects: the cosmic and the individual. The Cosmic Mind becomes the cause of the physical bodies as such, while the individual minds, which are limitations and reflections of the Cosmic Mind, become secondary creators not of bodies as such but of bodily relations and the experiences rising from them. Taken as a whole, the universe is an undivided constitution where an ultimate distinction between mechanistic and teleological laws cannot be made. The appearance of these two laws is due to a twofold phase in which the universe presents itself to the perception and conception of man. Leibniz, however, tries to bring about a reconciliation between mechanism and teleology, which is quite acceptable to the Vedanta.
Logical truths become identical with metaphysical realities only when the former are not confined to mere contents of human thought. It is the extension of human laws of thinking to the external universe that makes Leibniz think that the universe works according to logical and mathematical laws which hold good in the life of man. He even thinks that God, too, is bound by mathematical and logical laws and that a possible world that is created should not go counter to these laws. It is to be remembered that there is a great difference between the ways in which the individual minds function and the laws according to which the universe works. Though man is a part of Nature, he is not identical in quality with the objects of the universe in their essence. Physically, man is a part of the universe of physical bodies, and here he is identical in quality with the objects of the universe. But his mind is not identical in quality with the Cosmic Mind, for the human mind is not merely a quantitative limitation but also a reflection which divests the Cosmic Mind of its original, independent and indivisible nature. The universe as it is in itself and God, Who is the Soul of the universe, transcend the laws of relative thinking characteristic of the human mind. It is the common mistake of supposing that the universe is merely a collective totality of different individual constitutions that makes one come to the erroneous conclusion that the laws of human thought apply to the cosmic reality. God is beyond mathematical and logical laws which are valid only in a space-time world. The law of God transcends even the laws of the functioning of living organisms, though the latter too work in a manner different from that of mathematics and logic. If the laws of man and the laws of God were one, man would have easily perceived objectively the existence and the workings of God. The truth is that God is above even the conception of man; even the nature of the universe does not allow itself to become a content of the human mind. The laws of the universe and the laws of God defy human thinking, which is clear proof of the fact that there is a difference between human laws and objective universal laws.
Leibniz thinks that this is the best of several possible worlds created by God. The Vedanta tells us that there are different worlds of varying natures and that this is not necessarily to be considered the best of all possible worlds. Bhu-loka or the physical world is the lowest in a series of worlds culminating in satya-loka or the highest world of truth. There are transparent permeable worlds which reflect the divine consciousness in a greater degree than this physical world does. Worlds are created by Ishvara with due regard to the latent impressions embedded in the unmanifested minds of the unliberated individuals lying dormant and ready for manifestation at the end of the previous cycle. God does not create the world in an arbitrary manner, but draws the stuff of the world from the unmanifested potencies of the individuals to be created, which are to become the constituents of the would-be universe. We cannot say that any world is the best, unless it bears the highest approximation to the absolute Truth. The worlds that are created are merely fields provided for the experience of the different Jivas, or individuals, that inhabit the universe. The nature of the world that is created is just suited to bring about the necessary conditions required for the evolution of the individuals in a particular state of their existence. God creates the world not because it is good or bad, but because it is necessary for the purpose of cosmic evolution.
The theory of monads within monads is akin to the theory of the Yoga-Vasishtha that there are worlds within worlds. The worlds differ from one another not merely in quantity but also in quality, and the Yoga-Vasishtha tells us that these worlds can even interpenetrate one another without affecting one another or even being noticed by one another. How far Leibniz goes along this line is not made by him very clear, though he makes it possible for organisms to be contained in another organism.