The Theory of Momentariness by Śāntarakṣita, and Kamalaśīla and its Refutation by Śaṅkara

Śāntarakṣita and Kamalaśīla argue that destruction is neither a real entity nor a non-entity. They distinguish two senses of destruction. First, destruction as the intrinsic momentary nature of a thing (kṣaṇa-sthiti-dharma-rūpa-vināśa), which refers to transcendental impermanence. Second, destruction as empirical cessation or disruption (dhvaṃsa-rūpa-nāśa), which simply means the absence of the thing after it is no longer present.

A thing is called “destruction” in the first sense because it exists only for a moment; its very momentary existence entails its perishing. This intrinsic impermanence has a cause only in a special sense: the thing itself is the cause of its own destruction, since the fact of being momentary means that its production already implies its cessation. There is no external cause of this destruction. The notion that destruction occurs “immediately after” the thing does not apply here, because this intrinsic destruction arises together with the production of the momentary entity itself.

Empirical annihilation, on the other hand, is causeless in the sense that it is merely the non-presence of the object and does not affirm any positive entity called “destruction.” A kṣaṇa (moment) is not a temporal atom but the characteristic of being destroyed immediately upon arising. Thus, the momentary nature of a thing and the thing itself are not ultimately different; the distinction between a thing and its momentariness is a conceptual and linguistic construction. Though ultimately unreal, this distinction is pragmatically justified in ordinary discourse.

Only a momentary entity can be causally efficient, and hence truly existent. A permanent entity would produce all its effects simultaneously, since its causal power would always be present with no reason for delayed effects. If one claims that a permanent cause produces successive effects due to auxiliary conditions, then either those auxiliaries modify the cause or function independently. If they modify it, the modification becomes the real cause; if independent, their relation to the permanent cause becomes unintelligible. Relations like identity, production, or inherence fail to coherently explain the connection between a permanent cause and changing auxiliaries. Therefore, permanence undermines causal explanation.

Against objections from Naiyāyikas and Mīmāṃsakas regarding karma, recognition, and continuity, they respond that identity is merely similarity. Recognition arises from memory and conceptual imputation, just as a flame is treated as the “same” despite being a series of distinct flames. The notions of agent, experiencer, and personal unity are based on the imagined unity of a causal series, not on a real enduring self. Causation is defined as invariable antecedence: preceding moments generate succeeding moments. The cause arises in one moment, produces the effect in the next, and then perishes. Causality is nothing over and above causal efficiency, and existence itself is identified with efficiency. Thus, reality consists only of a stream of momentary states, whose apparent unity is a conceptual illusion. Bondage is the series of painful states produced by ignorance, and liberation is the cessation of that series through right knowledge. The doctrine of momentariness thereby rejects all permanent metaphysical entities such as Self, God, or primordial matter.

Refutation By Śaṅkara:

Śaṅkara argues that the Buddhist theory of momentariness is internally incoherent because it undermines the very possibility of causation, continuity, knowledge, and self-awareness.

First, a momentary entity cannot function as a cause of the succeeding moment. According to the doctrine of universal momentariness, the preceding moment ceases to exist precisely when the subsequent moment arises. If the cause has already perished, it cannot produce an effect. If it is said that the preceding moment, when fully developed, becomes the cause of the next moment, this presupposes some form of connection or persistence between the two moments, which contradicts strict momentariness. For causal efficacy requires a relation, and relation requires some form of continuity.

If one claims that the mere existence of the preceding moment is itself its causal activity, this too is untenable. An effect must in some way inherit the nature of its cause; otherwise causal linkage becomes unintelligible. But if the nature of the cause continues in the effect, then the cause is not entirely destroyed and thus cannot be strictly momentary. To admit causal transmission is implicitly to admit a form of persistence, which negates universal momentariness.

Śaṅkara further asks whether production and destruction are identical with the nature of a thing, merely different states of it, or entirely different entities. None of these options are coherent. If production and destruction are identical with the thing itself, then the thing collapses into mere arising and ceasing without any stable identity. If they are different states, then the thing must endure across multiple moments, which contradicts momentariness. If they are entirely different entities, then the thing becomes distinct from its production and destruction and thus permanent.

Moreover, if production is the beginning, existence the middle, and destruction the end, then the entity must span at least three temporal phases and therefore cannot be momentary. If production and destruction are reduced to perception and non-perception, then they belong to the mind rather than to the object itself, which again implies that the object persists independently of its momentary appearances.

The theory also collapses when confronted with causality and moral continuity. If things arise without causes, the Buddhist abandons dependent origination. If they arise from causes that last only until the effect appears, then cause and effect become effectively simultaneous, which contradicts the very notion of sequential production. Furthermore, karma becomes unintelligible: the agent who performs an action would perish before experiencing its result, leading to a breakdown of moral responsibility and continuity.

Śaṅkara then appeals to memory and recognition. Recognition of the past in the present presupposes a permanent synthesizing subject. Identity cannot be reduced to mere similarity, because similarity itself requires a subject that apprehends and compares multiple cognitions. Without a persisting knower, the unity of experience, memory, and knowledge becomes impossible.

He also rejects the Buddhist claim that momentary cognitions are self-luminous and self-apprehending. A cognition cannot illuminate itself, just as fire cannot burn itself. If every cognition required another cognition to know it, an infinite regress would follow. This regress is avoided only by positing a self-luminous, permanent self that apprehends all fleeting mental states. Ideas and cognitions, being momentary and manifold, cannot synthesize themselves into a coherent unity. Only a permanent witnessing self can serve as the subject that unifies the stream of experiences.