The term "Sankhya" is ultimately derived from the Sanskrit root khya, meaning "to know", and the prefix san, "exact". Exact knowing is most adequately represented by Sankhya, "number", and since the precision of numbers requires meticulous discernment, Sankhya is that darshana which involves a thorough discernment of reality and is expressed through the enumeration of diverse categories of existence. Philosophically, Sankhya is dualistic in its discernment of the Self (purusha) from the non-self (prakriti). In distinguishing sharply between purusha, Self or Spirit, on the one hand, and prakriti, non-self or matter, on the other, the Sankhya standpoint requires a rigorous redefinition of numerous terms used by various schools. Even though later Sankhya freely drew from the Vedic-Upanishadic storehouse of wisdom which intimates a rich variety of philosophical views, its earliest concern does not appear to have been philosophical in the sense of delineating a comprehensive conceptual scheme which describes and explains reality. Early Sankhya asked, "What is real?" and only later on added the question, "How does it all fit together?"

Enumerations of the categories of reality varied with individual thinkers and historical periods, but the standard classification of twenty-five tattvas or fundamental principles of reality is useful for a general understanding of the darshana. Simply stated, Sankhya holds that two radically distinct realities exist: purusha, which can be translated "Spirit", "Self" or "pure consciousness", and mulaprakriti, or "pre-cosmic matter", "non-self" or "materiality". Nothing can be predicated of purusha except as a corrective negation; no positive attribute, process or intention can be affirmed of it, though it is behind all the activity of the world. It might be called the Perceiver or the Witness, but, strictly speaking, no intentionality can be implied by these words, and so purusha cannot be conceived primarily as a knower. Mulaprakriti, however, can be understood as pure potential because it undergoes ceaseless transformation at several levels. Thus, of the twenty-five traditional tattvas, only these two are distinct. The remaining twenty-three are transformations or modifications of mulaprakriti. Purusha and mulaprakriti stand outside conceptual cognition, which arises within the flux of the other tattvas. They abide outside space and time, are simple, independent and inherently unchanging, and they have no relation to one another apart from their universal, simultaneous and mutual presence.

Mulaprakriti is characterized by three qualities or gunas: sattva or intelligent and noetic activity, rajas or passionate and compulsive activity, and tamas or ignorant and impotent lethargy, represented in the Upanishads by the colours white, red and black. If mulaprakriti were the only ultimate reality, its qualities would have forever remained in a homogeneous balance, without undergoing change, evolution or transformation. Since purusha is co-present with mulaprakriti, the symmetrical homogeneity of mulaprakriti was disturbed, and this broken symmetry resulted in a progressive differentiation which became the world of ordinary experience. True knowledge or pure cognition demands a return to that primordial stillness which marks the utter disentanglement of Self from non-self. The process which moved the gunas out of their perfect mutual balance cannot be described or even alluded to through analogies, in part because the process occurred outside space and time (and gave rise to them), and in part because no description of what initiated this universal transformation can be given in the language of logically subsequent and therefore necessarily less universal change. In other words, all transformation known to the intellect occurs in some context – minimally that of the intellect itself – whilst the primordial process of transformation occurred out of all context, save for the mere co-presence of purusha and mulaprakriti.

This imbalance gave rise, first of all, logically speaking, to mahat or buddhi. These terms refer to universal consciousness, primordial consciousness or intellect in the classical and neo-Platonic sense of the word. Mahat in turn gave rise to ahankara, the sense of "I" or egoity. (Ahankara literally means "I-making".) Egoity as a principle or tattva generated a host of offspring or evolutes, the first of which was manas or mind, which is both the capacity for sensation and the mental ability to act, or intellectual volition. It also produced the five buddhindriyas or capacities for sensation: shrota (hearing), tvac (touching), chaksus (seeing), rasana (tasting) and ghrana (smelling). In addition to sensation, ahankara gave rise to their dynamic and material correlates, the five karmendriyas or capacities for action, and the five tanmatras or subtle elements. The five karmendriyas are vach (speaking), pani (grasping), pada (moving), payu (eliminating) and upastha (procreating), whilst the five tanmatras include shabda (sound), sparsha (touch), rupa (form), rasa (taste) and gandha (smell). The tanmatras are called "subtle" because they produce the mahabhutas or gross elements which can be perceived by ordinary human beings. They are akasha (aether or empirical space), vayu (air), tejas (fire, and by extension, light), ap (water) and prithivi (earth).

This seemingly elaborate system of the elements of existence (tattvas) is a rigorous attempt to reduce the kaleidoscope of reality to its simplest comprehensible components, without either engaging in a reductionism which explains away or denies what does not fit its classification, or falling prey to a facile monism which avoids a serious examination of visible and invisible Nature. Throughout the long history of Sankhya thought, enumerations have varied, but this general classification has held firm. Whilst some philosophers have suggested alternative orders of evolution, for instance, making the subtle elements give rise to the capacities for sensation and action, Ishvarakrishna expressed the classical consensus in offering this classification of twenty-five tattvas.

Once the fundamental enumeration was understood, Sankhya thinkers arranged the tattvas by sets to grasp more clearly their relationships to one another. At the most general level, purusha is neither generated nor generating, whilst mulaprakriti is ungenerated but generating. Buddhi, ahankara and the tanmatras are both generated and generating, and manas, the buddhindriyas, karmendriyas and mahabhutas are generated and do not generate anything in turn. In terms of their mutual relationships, one can speak of kinds of tattvas and indicate an order of dependence from the standpoint of the material world.

No matter how subtle and elaborate the analysis, however, one has at best described ways in which consciousness functions in prakriti, the material world. If one affirms that purusha and prakriti are radically and fundamentally separate, one cannot avoid the challenge which vexed Descartes: how can res cogitans, thinking substance, be in any way connected with res extensa, extended (material) substance? Sankhya avoided the most fundamental problem of Cartesian dualism by willingly admitting that there can be no connection, linkage or interaction between purusha and prakriti. Since consciousness is a fact, this exceptional claim involved a redefinition of consciousness itself. Consciousness is necessarily transcendent, unconnected with prakriti, and therefore it can have neither cognitive nor intuitive awareness, since those are activities which involve some centre or egoity and surrounding field from which it separates itself or with which it identifies. Egoity or perspective requires some mode of action, and all action involves the gunas, which belong exclusively to prakriti. Consciousness, purusha, is mere presence, sakshitva, without action, dynamics or content. Awareness, chittavritti, is therefore a function of prakriti, even though it would not have come into being – any more than anything would have evolved or the gunas would have become unstable – without the universal presence of purusha. Thus it is said that purusha is unique in that it is neither generated nor generating, whereas all other tattvas are either generating, generated or both.

In this view, mind is material. Given its capacity for awareness, it can intuit the presence of purusha, but it is not that purusha. All mental functions are part of the complex activity of prakriti. Consciousness is bare subjectivity without a shadow of objective content, and it cannot be said to have goals, desires or intentions. Purusha can be said to exist (sat) – indeed, it necessarily exists – and its essential and sole specifiable nature is chit, consciousness. Unlike the Vedantin atman, however, it cannot also be said to be ananda, bliss, for purusha is the pure witness, sakshi, with no causal connection to or participation in prakriti. Yet it is necessary, for the gunas could not be said to be active save in the presence of some principle of sentience. Without purusha there could be no prakriti. This is not the simple idealistic and phenomenological standpoint summarized in Berkeley's famous dictum, esse est percipi, "to be is to be perceived". Rather, it is closer to the recognition grounded in Newtonian mechanics that, should the universe achieve a condition of total entropy, it could not be said to exist, for there would be no possibility of differentiation in it. Nor could its existence be denied. The presence of purusha, according to Sankhya, is as necessary as is its utter lack of content.

Given the distinction between unqualified, unmodified subjectivity as true or pure consciousness, and awareness, which is the qualified appearance of consciousness in the world, consciousness appears as what it cannot be. It appears to cause and initiate, but cannot do so, since purusha cannot be said to be active in any sense; it appears to entertain ideas and chains of thought, but it can in reality do neither. Rather, the action of the gunas appears as the activity of consciousness until the actual nature of consciousness is realized. The extreme break with previous understanding resulting from this realization – that consciousness has no content and that content is not conscious – is emancipation, the freeing of purusha from false bondage to prakriti. It is akin to the Vedantin realization of atman free of any taint of maya, and the Buddhist realization of shunyata. Philosophical conceptualization is incapable of describing this realization, for pure consciousness can only appear, even to the subtlest cognitive understanding, as nothing. For Sankhya, purusha is not nothing, but it is nothing that partakes of prakriti (which all awareness does).

Sankhya's unusual distinction between consciousness and what are ordinarily considered its functions and contents implies an operational view of purusha. Even though no properties can be predicated of purusha, the mind or intellect intuits the necessity of consciousness behind it, as it were. That is, the mind becomes aware that it is not itself pure consciousness. Since this awareness arises in individual minds, purusha is recognized by one or another egoity. Without being able to attribute qualities to purusha, it must therefore be treated philosophically as a plurality. Hence it is said that there are literally innumerable purushas, none of which have any distinguishing characteristics. The Leibnizian law of the identity of indiscernibles cannot be applied to purusha, despite the philosophical temptation to do so, precisely because philosophy necessarily stops at the limit of prakriti. Purusha is outside space and time, and so is also beyond space-time identities. Since the minimum requirements of differentiation involve at least an indirect reference to either space or time, their negation in the concept of indiscernibility also involves such a reference, and cannot be applied to purusha. Even though Sankhya affirms a plurality of purushas, this stance is less the result of metaphysical certitude than of the limitations imposed by consistency of method. The plurality of purushas is the consequence of the limits of understanding.

Within the enormous and diverse history of Indian thought, the six darshanas viewed themselves and one another in two ways. Internally, each standpoint sought clarity, completeness and consistency without reference to other darshanas. Since, however, the darshanas were committed to the proposition that they were six separate and viable perspectives on the same reality, they readily drew upon one another's insights and terminology and forged mutually dependent relationships. They were less concerned with declaring one another true or false than with understanding the value and limitations of each in respect to a complete realization of the ultimate and divine nature of things. Whilst some Western philosophers have pointed to the unprovable Indian presupposition that the heart of existence is divine, the darshanas reverse this standpoint by affirming that the core of reality is, almost definitionally, the only basis for thinking of the divine. In other words, reality is the criterion of the divine, and no other standard can make philosophical sense of the sacred, much less give it a practical place in human psychology and ethics. In their later developments, the darshanas strengthened their internal conceptual structures and ethical architectonics by taking one another's positions as foils for self-clarification. Earlier developments were absorbed into later understanding and exposition. Historically, Sankhya assimilated and redefined much of what had originally belonged to Nyaya and Vaishesika, and even Mimansa, only to find much of its terminology and psychology incorporated into Vedanta, the most trenchantly philosophical of the darshanas. At the same time, later Sankhya borrowed freely from Vedantin philosophical concepts to rethink its own philosophical difficulties.

Despite Sankhya's unique distinction between consciousness and awareness, which allowed it to preserve its fundamental dualism in the face of monistic arguments – and thereby avoid the metaphysical problems attending monistic views – it could not avoid one fundamental philosophical question: What is it to say that prakriti is dynamic because of the presence of purusha? To say that prakriti reflects the presence of purusha, or that purusha is reflected in prakriti, preserves a rigid distinction between the two, for neither an object reflected in a mirror nor the mirror is affected by the other. But Sankhya characterizes the ordinary human condition as one of suffering, which is the manifest expression of the condition of avidya, ignorance. This condition arises because purusha falsely identifies with prakriti and its evolutes. Liberation, mukti, is the result of viveka, discrimination, which is the highest knowledge. Even though viveka might be equated with pure perception as the sakshi or Witness, the process of attaining it suggests either an intention on the part of purusha or a response on the part of prakriti, if not both. How then can purusha be said to have no relation, including no passive relation, to prakriti? Even Ishvarakrishna's enchanting metaphor of the dancer before the host of spectators does not answer the question, for there is a significant relationship between performer and audience.

Such questions are worthy of notice but are misplaced from the Sankhya standpoint. If philosophical understanding is inherently limited to the functions of the mind (which is an evolute of prakriti), it can encompass neither total awareness (purusha) nor the fact that both purusha and prakriti exist. This is the supreme and unanswerable mystery of Sankhya philosophy, the point at which Sankhya declares that questions must have an end. It is not, however, an unaskable or meaningless question. If its answer cannot be found in philosophy, that is because it is dissolved in mukti, freedom from ignorance, through perfect viveka, discrimination. In Sankhya as in Vedanta, philosophy ends where realization begins. Philosophy does not resolve the ultimate questions, even though it brings great clarity to cognition. Philosophy prepares, refines and orients the mind towards a significantly different activity, broadly called "meditation", the rigorous cultivation of clarity of discrimination and concentrated, pellucid insight. The possibility of this is provided for by Sankhya metaphysics through its stress on the asymmetry between purusha and prakriti, despite their co-presence. Prakriti depends on purusha, but purusha is independent of everything; purusha is pure consciousness, whilst prakriti is unself-conscious. Prakriti continues to evolve because individual selves in it do not realize that they are really purusha and, therefore, can separate themselves from prakriti, whilst there can never be complete annihilation of everything or of primordial matter.

Whereas Yoga accepted the postulates of Sankhya and also utilized its categories and classifications, all these being in accord with the experiences of developed yogins, there are significant divergences between Yoga and Sankhya. The oldest Yoga could have been agnostic in the sense implicit in the Rig Veda Hymn to Creation, but Patanjali's Yoga is distinctly theistic, diverging in this way from atheistic Sankhya. Whilst Sankhya is a speculative system, or at least a conceptual framework, Yoga is explicitly experiential and therefore linked to an established as well as evolving consensus among advanced yogins. This is both illustrated and reinforced by the fact that whereas Sankhya maps out the inner world of disciplined ideation in terms of thirteen evolutes – buddhi, ahankara, manas and the ten indriyas – Patanjali's Yoga subsumes all these under chitta or consciousness, which is resilient, elastic and dynamic, including the known, the conceivable, the cosmic as well as the unknown. Whereas Sankhya is one of the most self-sufficient or closed systems, Yoga retains, as a term and in its philosophy, a conspicuously open texture which characterizes all Indian thought at its best. From the Vedic hymns to even contemporary discourse, it is always open-ended in reference to cosmic and human evolution, degrees of adeptship and levels of initiatory illumination. It is ever seeing, reaching and aspiring, beyond the boundaries of the highest thought, volition and feeling; beyond worlds and rationalist systems and doctrinaire theologies; beyond the limits of inspired utterance as well as all languages and all possible modes of creative expression. Philosophy and mathematics, poetry and myth, idea and icon, are all invaluable aids to the image-making faculty, but they all must point beyond themselves, whilst they coalesce and collapse in the unfathomable depths of the Ineffable, before which the best minds and hearts must whisper neti neti, "not this, not that". There is only the Soundless Sound, the ceaseless AUM in Boundless Space and Eternal Duration.

Hermes, July 1988
by Raghavan Iyer