John Locke, as an empiricist, refutes the rationalistic doctrine of innate ideas. There are no inborn truths for Locke. All knowledge is empirical, received through the senses. The mind has no private truths. It is originally a tabula rasa, a blank tablet, on which external things make their impression through the senses. Even our inward ideas are products of outward sensations. The mind cannot have its own ideas independent of sense-perception. We know nothing that is not perceived through the senses or reflected by the mind on the basis of sense-perception. Sensuous and reflective experience is therefore the ground of all our knowledge. Sensation and reflection constitute the whole of our experience. The mind formulates ideas and reflects on the basis of sense-perception. Simple ideas received by means of sense can be converted into complex ideas by the mind; but the mind does not create new ideas, nor destroy them.
Locke distinguishes between ideas produced by mere sensation, which may not correspond to the actual properties of things outside, and those which really correspond to them. The qualities of things which create ideas through sensations and which do not correspond to their real properties are called secondary qualities, while those qualities in things which produce sensations and ideas corresponding to their inherent properties are called primary qualities. Solidity, extension etc. are considered to be the real properties of things and so they are primary qualities, while colours, sounds etc. are not qualities inherent in things, and so they are secondary qualities. The primary qualities are really present in things, while the secondary ones are not. Our knowledge is confined to the perception of the secondary and the primary qualities, received through sensations, external and internal, though the mind can convert our simple ideas of these sensations into complex ones. Our ideas of things or substances are derived by sensation and reflection; the substances are merely assumed as existent on account of the sensation of the qualities and the formation of the ideas. Substance, mode and relation are just complex ideas of sensations and cannot pretend to be anything more. We have only a representation in our minds of the real things outside; we do not perceive them directly. What we know are only the secondary and primary qualities, not the substances in which they inhere.
The world outside is independent of the mind. It is the presence of the real objects that causes in us real sensations. The world consists of substances, in which qualities and actions inhere. According to Locke, there are two kinds of substances: bodies and souls. We perceive bodies and have a clear and immediate idea of our soul. We know bodies through sensation and the soul by reflection. Thought is an activity which inheres in the soul. Bodies are material and souls immaterial. From the perception of physical qualities their basic substance is assumed, for qualities cannot simply hang in the air, they must have a substratum. Similarly from the observation of mental operations, a notion of their basis, a spiritual soul, is formed.
Locke admits that there is interaction between body and mind, both of which are real beings. All our ideas are the results of the action of bodies on our minds. The soul experiences changes on account of its being acted on by bodies outside. Locke does not think that our perception of the external world is clearer than our notion of the reality or existence of the soul, or that we are surer of the nature of bodies than that of souls. He would rather say that our idea of the soul and its action is clearer and more distinct than that we have regarding material bodies. Our knowledge of bodies outside is not certain knowledge; the secondary qualities which we perceive do no represent the reality of things. The secondary qualities are produced not by the things as such, but by the primary qualities which inhere in things and which really belong to things. The primary qualities really represent things.
But Locke tells us that bodies affect not minds or consciousness, but only bodies, and physical motion can affect only physical motion. How, then, can Locke justify his theory of representationism, which holds that we receive mental images of physical substances that exist outside in reality? This is a difficulty which Locke does not seek to solve. He merely adds that this is possible on account of God's arranging the properties of bodies and of motion in such a way that they can act thus. He, however, becomes bold when he says that we cannot even understand how bodies act on bodies, or how motion produces motion. When we are content to be ignorant of this mystery, why not hold the same attitude towards the action of bodies on senses and minds, seems to be Locke's rejoinder to our objection to his theory of knowledge. We end in mystery. He is satisfied with telling us that we have sensations in this way, and there ends the matter. He is not concerned with the question how they are caused.
Locke is sometimes very candid in doubting whether it is minds or souls alone that think or whether matter, too, can think. When we do not know the essential nature of things, how can we say that minds alone think and not matter? Perhaps what we call soul is only matter, and perhaps matter can be conscious. Locke's misgivings in regard to this problem lose much of their value when we become alive to the fact that what is important is not whether the source of consciousness is matter or mind but that consciousness is the essential characteristic of experience. When we attribute consciousness to matter, what we actually do is to deny the materiality of matter, and to make it a conscious entity; in other words, what we apparently call matter becomes soul in reality. Anyway, the fact remains that the essential nature of the Self or the experiencer is consciousness, name it matter or soul.
In spite of these misgivings that he has, Locke appeals to commonsense and admits that there are two substances: material and mental. Material bodies, according to him, are constituted of minute corpuscles or atoms (or perhaps molecules) which are endowed with the primary qualities. These form the essential active elements of which matter is the embodiment. These again are the bases of the secondary qualities. But Locke says that we cannot know these corpuscles, what their properties are, how they are united, how they act or move. One is tempted to add that Locke could have as well said that we do not know what matter consists of. For his corpuscular theory does not in any way increase the fund of our knowledge. It only states something together with a note that we do not know what is thus stated. That the constitution of matter empirically presents itself as a conglomeration of minute particles,—call these corpuscles, atoms or molecules,—the Vedanta has no objection to admit. For it matter is governed by the laws of space-time and mechanical motion, as long as our perception or observation of matter is limited to the laws to which space, time and causation are subject. Only it would add that this is not all that we have to say about matter. Matter has a higher nature and purpose, which the senses cannot comprehend, and which points to the realisation of a perfection that transcends human nature and its laws. Physical and chemical laws are not denied; only we are advised not to forget that these laws are valid only in the phenomenal world of sense and understanding and that they cannot pretend to explain the final nature of things. Reality is not confined to what we experience empirically.
Locke, like Descartes, admits a third substance, viz., God. He tries to prove the existence of God not from innate ideas, as Descartes has done,—but from sense-experience. According to Locke, we form an idea of God by enlarging or carrying to infinity the laws and objects of our sensations and reflections. Existence, extension, knowledge, power etc. are what we experience, and their infinitude is our idea of God. We do not know God's essence or reality. To the Vedanta, the existence of God is known intuitively, not through sensations. It is not possible for us to form an idea of unity by accumulating the materials supplied to us by the senses. A collection of particulars may give us a vast universe of plurality, but our conception of God points to the reality of something which is not only an undivided wholeness but Consciousness in essence. Consciousness does not become an object of the senses, for what we know through the senses are material bodies. We have an immediate intuitive perception of the existence of Consciousness, which is not deduced from some other premises. Consciousness itself is the fundamental premise from which all other facts are experienced or logically deduced. No doubt, this intuitive perception of the existence of an Infinite Being or Consciousness is not very clear and remains indistinct and hazy in ordinary individuals, and so this admission of the fact of the existence of an Infinite Consciousness is clothed in empirical attributes, such as unlimited extension in space, endless existence in time, limitless knowledge and power, and so on. The Vedanta further says that the essential characteristics of God, as we conceive of Him, are the opposites of the experiences we have in ordinary life. We observe that the world is changing and so we conceive of God as its changeless and eternal substratum. We perceive that objects of our knowledge are inert in nature and so we endow God with supreme intelligence. We experience limitation and pain here; so we conceive of God as absolute freedom and bliss. But it does not mean that God is merely an embodiment of these negative attributes which appear to be the counter-correlatives of relative experience. God, to the Vedanta, is above our conception of existence, knowledge, power and bliss. He is absolutely transcendent and His positive nature cannot be known by us except in direct realisation. Locke also gives us the usual cosmological and teleological proofs for the existence of God, stating that man, who, he knows, is a real being, must have a cause, and the eternal cause of all real beings must be a perfect being that exists and is real. In fine, it is to be noted that Locke's position that objects exist, but they cannot be known; that the soul exists, but it cannot be known; and that God exists, but He cannot be known, leads to great difficulties which he did not foresee, and naturally gives way to the conclusion that we know nothing at all except only sensations and ideas. He paves the way to the mentalism of Berkeley and the scepticism of Hume.
That the mind remains a blank tablet when one is a child is not acceptable to the Vedanta, for the mind of even a child is filled with several impressions of past lives, though dormant and unexpressed. We have examples of child-geniuses, which defy Locke's theory of crass empiricism. If we understand by innate ideas those lying latent in the mind, being results of experiences one had in previous lives, we cannot deny that innate ideas are present even in the mind of a child. Not only this; we have innate ideas of a different kind, too. The conviction that we have in regard to the existence of an experiencing self and as its implication the existence of God is certainly not derived from sense-experience. It is embedded in our minds as a necessary and universal truth. Even the truths of mathematics and logic are not exclusively derived from sense-experience. Though the material necessary for the formulation of mathematical and logical laws is received by us through sensations, the laws themselves are not got from empirical observation; they are inherent in the mind itself as its essential make-up and method of working. Kant has shown how empiricism does not give us the whole of truth.
Locke merely states that matter exists, though it cannot be known independent of the primary and the secondary qualities. It only means that we know only these qualities and to posit a matter beyond them is unwarranted. It would mean that we know the existence of substances through inference and not perception. The secondary qualities are the effects of a mutual interaction of the perceiving subject and the perceived object and thus do not form properties of matter. The same thing can be said of the primary qualities, for they too are known to us only through the senses. Thus even the primary qualities would not give us a true representation of things as such. If it is said that extension, solidity etc. are universally perceived, we may say that colours, sounds etc. are too perceived universally. And if it is said that colours, sounds etc. are not perceived to be the essential properties of things, we add that there is no warrant whatsoever to consider even the primary qualities as the essential properties of things. The primary qualities too are just reactions produced by the interaction of the subject and the object. We never perceive the primary qualities without the secondary qualities. By this it would mean that we cannot make a distinction between the primary and the secondary qualities, which means that we know nothing real in itself, and that we cannot know anything beyond these qualities. Locke could not anticipate the consequences of his suppositions; we notice these when his views are carried to their logical limits by Berkeley and Hume.
Locke thinks that the moral ideas come to us from outside, and that there is no absolute necessity or universality about them. As with the knowledge of objects outside, so with the moral commands. They do not come from within but from without. Locke says that we teach moral precepts to children who, when they grow up, think that these precepts are received from God or from the inner conscience. Right and wrong are notions framed in accordance with the laws learnt form outside. People frame these rules keeping in view the acquisition of happiness and the avoidance of pain. Locke's view is that what tends to pleasure is called by us good and what brings pain evil. Public happiness and the happiness of oneself determine goodness. Locke says that God has so arranged things that virtue and happiness go together, so that virtue is necessary for the attainment of happiness. When the public approve of an act we call it virtuous. The Vedanta, on the other hand, tells us that ethics is based on the metaphysics of reality. Morality is not what is sanctioned by public opinion or what is conducive to mere pleasure or happiness. The right is that which directly or indirectly becomes conducive to the realisation of the Absolute and has nothing to do with the social position of man. It may be true that we learn many of the moral principles by receiving instructions from others, but this does not mean in any way that these principles are just conventional rules and have no absolute validity. What is taught as a moral precept is expected to conform to the law of the Self-realisation of the individual. Moreover, there are certain moral principles which present themselves as inner commands, though these commands can be known only by a highly cultured and purified conscience and understanding. To the Vedanta, what is good or virtuous is not what is merely considered to be in accordance with the methods of acquiring social happiness. The Vedanta would agree with the view that virtue is that which tends to happiness only when happiness is understood in the sense of the beatitude of the Absolute. Human happiness is not the goal of virtue or goodness. The Vedanta notices that man is never satisfied with anything that is provided to him in this world, and so there is no such thing as a real happiness which he may seek after. The right or the good has therefore to be defined as that which is conducive to unsurpassed happiness, which is the bliss of God-Being. Even the public good should be in conformity with this highest good, which can be realised only in the Divine. It is needless to say that one's own good is non-different from this. The concomitance of virtue with happiness is not an accidental happening or the result of an arbitrary decree from God outside. Virtue is the name we give to the nature of our thoughts, words and actions when they conform to the law of the attainment of real happiness, which is the centre of Absolute-Experience. It is not fear of punishment that determines virtue or goodness but a higher need, which is a manifestation of the supreme urge for Self-realisation. We may have individual morality, social morality, political morality or different provinces of application of the moral principles, but all these have to be in perfect agreement with the universal law of the Absolute. What we call virtue, goodness or a moral law is not a creature of man's mind, but the very form that is taken in this world by the universal law of the Divine. All crave for unlimited happiness, though it cannot be had in this world. This eternal longing points to the existence of a Supreme Being in which all our aspirations find their consummation.