The Sankhya and other systems; thus ends the Sankhya, with its sixty topics, to which the author of the Sankhya-karika has referred; and it constitutes the great foundation of thought upon which the remaining systems have been reared. Indeed, to understand the Sankhya is to understand the basis of all these systems, for they too deal with the same topics, but from different points of view, and are but an amplification, commentary or criticism of its ideas and conclusions.
For instance, the Sankhya believes that the chief object of a man's life is to put an end to all kinds of pain, and that is possible only by means of pure knowledge and renunciation of action. As, however, the idea and scope of this knowledge has not been defined by the Sankhya, Nyaya explains what it is, and tells us that it consists in the knowledge of sixteen categories of things, which are condensed into six by the Vaiseshika.
The Mimansa correlates both knowledge and action in its idea of Dharma; and Yoga, while admitting that renunciation of action is the ultimate goal of life, seeks to reconcile knowledge with action so long as it lasts. But Vedanta attempts to eliminate the difference between the two by showing that knowledge itself is a form of action and that there can be no action without knowledge; and so we have to look for a solution of the problem in some other direction.
Three heads of comparison: The different conclusions of the Sankhya accordingly lend themselves to a variety of opinion, and it is this that is presented by the other systems. It would be convenient to group together the main ideas of the Sankhya under three heads, Prakrti, Soul, and God and compare them briefly with those of other systems; and that will enable us to understand the latter in their proper perspective.
Prakrti: With regard to Prakrti or Nature, the Sankhya tells us that it is the supreme creator of life, of all things except the soul; and the idea of its evolution is obtained by means of inference. It is necessary to understand what this means.
Man as a microcosm: There can be no idea of existence without knowledge; and, according to the ancients, existence and knowledge are synonymous terms. Again, knowledge, so far as man is concerned, is limited to human knowledge, that is, all that it is possible for man to know; and it is conditioned by his faculties, the senses acting in association with their objects, mind, ahankara (I-as-an-actor or ego), intellect and the soul; and is limited to what they can grasp, and to the objects to which they can react. There may be many things in the universe; but if we are not aware of them, or they are beyond our reach, they do not exist so far as man is concerned. Hence, all of life that exists for man in the universe consists of what lies within and without him, the soul, intellect, ahankara, mind, senses and their objects; and it is for this reason that he was conceived to be a microcosm, a miniature of the universe.
Prakrti as a creator: The Sankhya does not conceive of Prakrti as a creator of the soul. Indeed, it could not do so, for it would have rendered nugatory its own conception of freedom from the bondage of life; and so its evolution is limited to the intellect and the rest, while the soul is said to have an independent existence of its own.
The meaning of Prakrti: The Sankhya defines Prakrti as a state of equilibrium or rest of the three Gunas or the attributes of objects, which arise out of it; and this obviously means that, as evolution or creation is a kind of action, we can form a proper idea of it only with reference to a previous state of rest. Prakrti may accordingly be said to be "a great action in the making", and that indeed is the literal meaning of the word". It is also unmanifest in its original state, and becomes manifest when it evolves into different forms of life.
Prakrti or pra-krti means "(pra) great (krti) action"; or "(krti) action (pra) going forth". It may therefore be said to be a fountain of great action, or a great action about to "go forth" or make things manifest.
The process of action: We have observed that the evolution of Prakrti into intellect and the rest is a form of action; and if, as the Sankhya tells us, its idea is based on inference, it can only mean that it is based on the idea of the process of action from a state of rest in the case of man.
Now we find that before an action can take place, there must be a decision to act; and the latter is a function of the intellect. Thus, the first form of activity, following a state of equilibrium or rest, is that of the intellect; and so the Sankhya tells us that Mahat or Intellect is the first to arise from Prakrti in its state of equilibrium or rest.
The next stage in the process of action is the necessity of the existence of an actor; and that is Ahankara (or I-as-an- actor) which, as the Sankhya tells us, arises out of the Intellect. But the actor cannot act without desire, which is an attribute of the mind; and so the Mind is said to arise out of Ahankara in the next order of creation.
Again, the mind cannot function without reference to the senses of knowledge and action; and so they are the next in order to arise. Finally, as the senses cannot function without reference to their objects, we have the great "elements" and their properties to complete the tale.
A general agreement: That is how the idea of Prakrti and its evolution may be said to have been obtained by means of inference; and, as there can be little difference of opinion on the subject, there is, except for some clarification on certain points, little reference to it in the remaining systems.
The soul: The central idea of the Sankhya, in connection with the chief problems of life, refers to the soul. According to the Sankhya, the soul exists, for we cannot deny its existence; and it is because of its existence in the body that all the other faculties of man are able to act. But it is altogether different from Prakrti and all that arises from it; and we say so because we find that, at one time or another, it desires to make itself free from all association with the latter. Were it of the same kind, it would not have this desire.
The desire to become free postulates that the soul understands the nature of freedom; and that is possible only if it has been free at some time. Hence we may assume that the soul, before it is born for the first time or comes to be associated with Prakrti, is free.
It is not possible to explain how the soul came to be associated with Prakrti for the first time; but we cannot deny that it dwells in the body and so is associated with it, and desires to make itself free. Its chief problem accordingly is how to secure this freedom. It is, however, possible to say that this association is caused by some inexplicable attraction between Prakrti and the soul. But it is this that is the primary cause of all human sorrow and pain, which it is the object of a man's life to bring to an end.
The world is full of sorrow, for there is no one who is really happy. Indeed, there is no real joy in life; and pleasure itself may be said to be a form of pain, for it soon turns into it. The principal cause of this sorrow and pain is action or change, conceived in its widest significance; and it is all due to Prakrti or Nature, which is subject to incessant change.
The soul feels this pain because of its association with the body, which is a part of Prakrti or Nature, and so subject to change. Indeed, it feels it still more because, through some strange misconception, it imagines itself to be an actor, though it is really not so and so identifies itself with ahankara or the I-as--an-actor, which is a part of Nature and abides within the body like the intellect, mind, and the senses, which too have been created by Prakrti.
This being so, the soul can make itself free again only by understanding its true character as soul, as something altogether different from ahankara and all other faculties or organs of the body. Then, if it ceases to have any association with ahankara or the I-as-an-actor, and refrains from all action or association with action, it can make itself free from all that belongs to Nature or Prakrti. There are thus two means of attaining to freedom, self-knowledge and a complete renunciation of action.
But this self-knowledge implies a perfect knowledge of all that is in Nature, for without it the soul cannot come to regard itself as something altogether different from it. Further, a complete renunciation of action can be achieved only by stages or degrees, for a person must act so long as he lives; and, as it is not possible to acquire perfect knowledge during one life-time, he must pass through many lives to be able to do so. Hence we must agree that the same soul is born again and again.
There is thus an almost endless continuity of life and its experiences; and death is only an interval between two lives. We find that there are innumerable souls in innumerable bodies, and each is different from the other; and, if all this is in accordance with a law and not due to the arbitrary will of an irresponsible creator, the only explanation of this difference is that the same soul is born again and again; but each soul is at a different stage of its journey of life; and, as the actions and experiences of each are different, the souls are different too.