Monism in Indian philosophy: the coherence, complexity, and connectivity of reality in Śaṃkara's arguments for Brahman

Abstract Classical Indian thought contains a number of arguments for monism that reject the cogency of metaphysical pluralism's account of change, development, and causation in the world. They do this on the basis of (a) the coherence of changes that we see in the world, (b) the difficulty of limning absolute distinctions between individuals, and (c) the prerequisite need for some medium explaining causal interactions. This article provides some background to Indian philosophical thought about a basic fabric of reality that grounds changing forms, containing the telos of their evolution in potentia. It then sets out Coherence, Complexity, and Connection Arguments for monism as employed by the Vedāntic scholastic philosopher Śaṃkara. Along the way, we clarify the Vedāntic conception of a single material, efficient, and formal cause that provides a medium for connection and combination, is naturally replete with generative order and impetus, and in which the teloi of all forms are embedded. We will briefly consider what the argument shows, if it succeeds – comparing with current philosophical approaches to monism. Finally, we observe that this rich monism, describing a single vertiginous reality of many levels and powers, is central to classical Hindu conceptions of what makes something ‘divine’.

environment, the Hindu Vedāntic schools assertedeach in its own waythat there is a unified 'real behind the real' from which all things come, by which they are pervaded and sustained, and into which they return. The name given to it was Brahman, a single universal reality that grounds matter, thought, and meaning. In the realist schools of Vedānta (which included its Bhedābheda 'differentiated non-difference' and Viśiṣṭādvaita 'qualified non-dual' traditions), empirical reality was described as arising through Brahman's 'flowing' or 'pouring out' into the specific forms of all things. This was likened to the way a spider emits a complex web from its own body, breath emerges to form variegated words and meanings, or a fire naturally flickers and expands without being depleted. It provided part of the general metaphysical world-view of mainstream Hinduism. This article sets out one of India's most common and compelling arguments for monismits linked arguments from formal coherence, combinability, and connection. It aims to show how Sāṃkhya's satkāryavāda theory that each entity is the actualization of potencies already existent in its prior causal ground, was combined with the early Vedāntic idea that the changing properties of the world inhere in a single underlying reality (sat), material cause (upādāna kāraṇa), or foundation (adhiṣṭhāna, avasthā, āśraya). The combination of these two conceptionsof causal powers and a grounding substrateinspired the distinctive notion of a unified ground that contains all of reality's forms, in their total ordered telic evolution, at all times.
Philosophically construed, the cornerstone of this Indian approach is its counterfactual argument that metaphysical pluralism should produce a world that is 'modally unconstrained in composition' (Schaffer (2010), 40 ). It does not; instead we see a generatively ordered world, and for this reason monism provides a better explanation than pluralism.
That the world appears connected in teleological formation, ontological constitution, and causal interaction is the basis for these Indian and Western families of monist arguments. Indeed, the connected, combinatory, and interactive nature of entities might be taken to suggest that the world has no definite parts so that 'there seems no objective ground for carving things in just one way ' (ibid., 48). This in turn could be taken to imply that the stuff of things is a rich 'gunk', to borrow Zimmerman's term (1996), perhaps with something like a 'statespace structure' (Sider, 2008) to explain the heterogeneous nature of the empirical world on which all reality is patternedfrom its most simple levels to its most entangled and emergent ones. It is because of this unified ground, it is claimed, that a 'cosmos' rather than a 'chaos' exists. The article also considers the way in which this super-causal rich monism provides the basis for classical philosophical conceptions of divinity.
The last point is an important one for understanding the role of monism in Indian philosophy of religion. Hinduism's Vedāntic tradition praised the divinein the form of Brahmanas the pervasive ground of all, facilitating the constant emergence of new forms with new powers. Key religious texts, like the Upaniṣads and the Bhagavad Gītā, expressed the monist 'view from within', in which each visible form of the world becomes a window onto a more universal reality instantiated in it. But only the philosopher who had inferred its presence, and learned to spot it underneath the world's forms, 3 could look at his environment and say to the One: You are a boy or also a girl. As an old man, you totter along with a walking stick. As you are born, you turn your face in every direction. You are the dark blue bird, the green one with red eyes, the rain-cloud, the seasons, and the oceans. You live as one without a beginning because of your pervasiveness, you, from whom all beings have been born. 4 Debates flowing from this conception pitted the creation-related divine attributes of aseity and creativity, pervasion and omnipresence, against the (apparently) contrary attributes of immutability, simplicity, and transcendence. But what reason could the monists have for arguing that the world of empirical experience is really 'part of' an all-encompassing monistic reality?
In this article we will do four things. First, we will contextualize India's notion that some single foundation must underlie the universe, bringing into focus three texts that formed a recurring point of reference. Second, we look at the development of this idea in the standard Vedāntic arguments for monism as put forward by the c. eighth-century scholastic thinker Śaṃkara. Third, we will consider some of the philosophical implications of this monism, and fourth, consider the idea that what makes Brahman sacred is its nature as a universal super-causal ground possessing all reality in potentia, rather than merely an inert 'stuff' that builds upward blindly and contingently.
Early foundations: substrate, satkā ryavā da, and global causation As early as the beginning of the first millennium BCE, Vedic texts expressed a nascent metaphysical intuition toward monism in the idea that there must be (a) some 'fabric' of which the cosmos as a whole is made, and (b) some encompassing context or grounding foundation that upholds it. Classical cosmogonic speculations asked 'What was the foundation and the support' of the universe (Ṛg Veda 10.129.1), what was the 'forest' from which the world's 'wood' came (Ṛg Veda 10.82.4), on what 'pillar' does reality rest (Atharva Veda 10.7), and from what was the creator's 'flesh' formed (Atharva Veda 10.2.1). 5 These ancient texts imply that the phenomena of the universe require a stuff, or a somewheresome prior settingin order to exist as a cosmos. Yet the assumption that the empirical world requires some further ground was also vigorous disputed by Buddhist sceptics and Cārvāka empiricists. Although many texts and debates contributed to the development of this argument, we will focus on three influential texts -Chāndogya Upaniṣad 6. 1.4, Sāṃkhya and the Brahma Sūtrasthat contributed three components: (i) some kind of grounding substrate is evidenced by the continuous and consistent properties that extend beyond individual objects, and appear to identify a more extensive level of their existence (like the clay that outlasts and underpins a statue), (ii) an invisible form of what a thing becomes must exist prior to its appearance in that from which it emerges, and (iii) coherent patterns of development and causation across contexts warrant some global explanation that unites them. These ideas, cumulatively implying a pervasive ground that serves as an ordering cause, formed complementary components of the Indian monist's argument.
Early texts like the Chāndogya Upaniṣad touched on the idea of a shared continuous level beyond the fleeting appearances that constitute reality. It identified this pervasive reality as Brahman, a term largely used in this early literature to signify the all-pervading cause of all, from which beings arise, by which they are conserved in existence, and into which they return. 'Objects' were interpreted as transformations (vikāra) of an underlying material, with their individual 'given names' revealed as mere 'verbal handles' (nāmadheya and vāc-ārambhaṇa). Once equipped with generalizing and predictive inference, or anumāna, we are able to identify this changeless level in all entities. Where early thinkers had wondered whether it was pure chance ( yadṛcchā) or some kind of intrinsic disposition (svabhāva), or even some fateful natural order (niyati) that shaped the world (see Bhattacharya (2012)), this view held that something underpins the span of changes with a deeper level of identity. Individuals are merely transformations of the underlying substrate, picked out by the conventional names that we attribute to them; by implication our usual 'common-sense' filter we apply to our empirical observations obscures reality. The later school of Advaita Vedānta used this idea that empirical forms are merely conventional and misleading to develop an idealistic 'illusionist' school. Meanwhile the realist Vedāntic schools of Bhedābheda and Viśiṣṭādvaita sought ways to explain the transformation (pariṇāma) of the substrate into diverse forms.
Alongside this Vedāntic conception of Brahman as a changeless level of identity, another metaphysical school developed a similar notion of a prime matterbut emphasized that it is not just appearances, but also whole trajectories of change that are grounded by this level, existing in potentia 'in' it at all times. This produces the phenomena we know as objects enduring through change. The school was Sāṃkhya, and its influential causal theory was called sat-kārya-vāda, literally the existent (sat) effects (kārya) theory (vāda). The theory held that that forms exist in potentia together at all times, but manifest at different times. It was one of a number of Indian answers to widely recognized philosophical problems raised by the idea of something coming into existence. 6 This distinguished between the realness of things (all of a thing's forms are 'real' regardless of whether they happen to be manifested at a certain time and place or not), from their present, visible actualization. A pithy text called the Sāṃkhya Kārikā hinted at arguments that there is a substrate underlying change, and that it contains its future manifestations. These became go-to arguments for the many schools that adopted the satkāryavāda theory. Meanwhile, holders of the contending 'no-prior-existence of effects in their cause' or asatkāryavāda view (such as the Vaiśeṣika atomist school) used the example of a weaver weaving thread from cloths to show that individual threads have no natural connection with the cloth they come from; they need an efficient causea weaver. So too, efficient causation shows that satkāryavāda's purely 'prior dispositions' account of change was inadequate. Sāṃkhya countered this with the example of things that naturally develop into new forms: a seed growing into a tree, or milk naturally maturing into curds. The terse argument in the Sāṃkhya Kārikā runs: But generality is ascertained from what is seen by going beyond the senses through inference (anumāna) . .  The manifest [form] possesses a cause, is not eternal, is not pervasive, is active, is not one, is dependent, is an observable sign, is composite, and is affected by others. The unmanifest [substrate] is the opposite. The unmanifest has three elements (there was a commonly accepted set of three key cosmic elements), is indiscernible, is not an object, is general, is insentient, and is productive; thus is the prime matter. 7 Later, in a different passage the text tries to emphasize that inference which moves backward from the effect to the cause is a valid step in establishing the unseen existence of a substrate: From its having a nature [shared with] the qualities of the cause we establish that the cause is unmanifest [before its appearance] . . . and because of the transformation of the differentiations, from their conjunction, from the potency to evolve, from the separation of cause and effect, and from non-distinction of what is multi-formed, the unmanifest is the cause, generating the three elements, combinations, and transformation naturally (salīlavat), from being the object-field (āśraya) of one quality after another. (Sāṃkhya  Here the reasons seem to include a number of allied points. First, one should reject spontaneous causation or development on the basis that there is no empirical precedent for things happening without a cause: stasis is to be expected unless there is a prompt for change. Second, we generally perceive some unchanging material constitution that is different from the changing forms a thing takes and can be identified by certain continuous qualities. This suggests a sense in which the object as we see it existed before its appearance. Third, we commonly see constant correlation of dispositional types: the conjunction of certain kinds of causes with certain kinds of effects is ubiquitous and consistently ordered across times, places, and contexts. A seed can become a tree, an embryo can become an animal, and milk can become curds . . . but these prior causes cannot generate each other's effects. This universal order of concomitant conjunction suggests some shared causal constraint pre-existing innately in the cause that determines the range of possible effects. 9 Fourth, it argues that there must be a shared ontological medium facilitating the combinability of observed things, allowing them to merge and disjoin. Broadly contemporary to the Sāṃkhya Kārikā, Vedāntic thinkers developed their own tersely formulated treatise called the Brahma Sūtras. The text was more a mnemonic tool than an explicit explanation, and its sentences are so terse as to be opaque. Nevertheless, a number of sections clearly oppose the views of other schools of the time, attacking the competing 'prime matter' doctrine of Sāṃkhya on the one hand, the radical pluralism of Vaiśeṣika atomists and the ontologically nihilistic pluralism of Buddhist phenomenalists on the other, as well as Buddhist idealists (Yogacāra), antifoundationalists (Madhyamaka), and the Jain school of thought. One defence against pluralism draws on the Chāndogya Upaniṣad's idea of a pervasive and persistent 'sat' reality under the changing object-identity 'handles' of empirical appearance (Brahma Sūtra 1.4.1-20). The text also borrows Sāṃkhya's satkāryavāda argument and the example of milk, 10 but gives reasons why the prime matter that Sāṃkhya inferred is not an adequate account, largely because it cannot explain the existence of order (racana) or creative impulsion ( pravṛtti). 11 These ideas evolved through the course of debates hinted at in philosophical passages in Hindu epic literature and in the late classical to early medieval theological texts called the Purāṇās, and came to fruition in scholastic arguments such as the one we will trace below.

Śam ̣ kara's arguments for monism
The Brahma Sūtras brought into sharper focus pluralism's difficulty in explaining the continuous and coherent arrangement of the world's individual forms. As we will see, it seemed to emphasize that without some underlying unifying medium, nothing could interact or combine, and anything could causally come from anything; that is, pluralism can explain neither ontological and causal entanglement, nor telic, ordered change. One of the earliest texts that we have today expounding these points is the commentary of the great monist-idealist Śaṃkara. He is primarily known for his 'illusionist' doctrine, which held that empirical phenomena are merely imagined cognitions projected onto the one real object of Brahman. Yet in defending Brahman against pluralism, he used the classic defences of monism drawn from the Sāṃkhya Kāṛikā and Brahma Sūtras; here we draw on his account because it provides an accessible example of the arguments in fairly standard form.
In following them, it is helpful to have a clear picture of the contrasting views Śaṃkara sought to refute. The Vaiśeṣika 'atomist' school was pluralist in its metaphysics, holding (in brief) that there are multiple atomic components that interlink into the full complement of structures needed to constitute ontological 'objects' existing in time. The different kinds of these plural basic entities seemed to account for reality: substances and properties together made up what we think of as existing 'stuff', actions explained temporal change, distinctness and similarity seemed to explain the formal structure of similar and contrastive relations between things/ideas/events, and inherence was the bond that glued it all together. Causal coherence was explained by the universal menu of core ontological types. The medium of interaction was explained largely by inherence bonds that could shift and allow new types to align. But even Vaiśeṣika felt uncomfortable using this to explain the continuing coherent structure of empirical reality, and its deus ex machina solution was to develop a Hindu teleological argument: it filled the 'formalcause'-shaped gap in their metaphysics by positing Īśvarathe creator deity, as the 'disposer' of reality who ensures the continuous order of the universe.
By contrast, the phenomenalism of the Abhidharma Buddhist school adopted a more ontologically parsimonious solution. Abhidharma Buddhists believed that entities are just the patterns of similar adjacent phenomenal instants in flux, and used the notion of Correlated Appearing ( pratītya samutpāda, literally 'following one after another') to describe the unexplained natural tendency of these phenomena to follow on similarly after each other in a way that is both continuous moment-to-moment and structured in a continuous way across contexts. Like David Hume, the Abhidharma Buddhists were reluctant to say more than that coherence happens, and held that the tendency toward correlation that we observe in the world should not be reified into a causal agency or 'force' of nature. Yet correlated appearing was used in philosophical argumentation to do explanatory work, and opponents argued that this branch of Buddhism seemed happy to infer all sorts of general metaphysical truths in constructing their positions, but professed methodological agnosticism on the one point about which their own explanations were weakest. If they refused to infer a cause of global order, then their other inferences also had to go. In many respects pratītya samutpāda did the same work as the notion of īśvara in Vaiśeṣika. Effectively, it either reinstated a metaphysical principle at the heart of Buddhism, or implied that the phenomena themselves have some svabhāva or intrinsic nature. Śaṃkara's arguments below aimed to show that, contrary to these accounts, satkāryavāda must be generalized to the changing, dynamic, ordered whole of reality itself in order to account for (i) coherence, (ii) the ability of things to combine and recombine ontologically, and (iii) their ability to interact at all.

The Coherence Argument: consistent global order
Śaṃkara emphasized at least three key arguments against pluralism. One we will call the Coherence Argument. Much of the commentary to Brahma Sūtras verse 2.2.18 rolls out successive reasons why the material cause that exists prior to a thing's appearance should be taken as the cause of that thing's coming to be, and why those things must have a prior existence in potentia in their material cause. In short, he marshals a barrage of defences of satkāryavāda. But fittingly, given Vedānta's goal of globalizing satkāryavāda, his argument speaks not merely to individual objects, but to the consistency of change and causation across entities, times, and contexts. It begins as follows: In the world it is seen that people wanting curds, pots, necklaces, etc. take up their well-established respective (material) causesmilk, clay, gold, etc.not that a man wanting curds takes up earth, or a man wanting a pot takes up milk. This fact does not fit in with the theory of the non-existence of the effect before origination. If everything were equally non-existent everywhere before creation, why should curds be produced from milk alone and not from clay; and why should a pot come out of clay and not out of milk? (ŚBSB 2. 2.18) 12 The passage argues for satkāryavāda based on the invariable concomitance of trajectories of development. In a pluralist's world, there would be no reason why any given thing should not result from anything elseseeds could become tigers, tiger cubs could spontaneously become trees or exploding stars, old men could become infants or wisps of smoke, etc. The argument bears some similarities with teleological arguments which reason that order in nature must have some cause. But the solution here is not to posit the will or deliberative intention of a deity; it accepts the inference that design must be hardwired or 'front-loaded' into the system, but instead of positing a mind it sees coherent structured development as part of the intrinsic nature of the source material. Further, it notes that this hard-wiring is global rather than local. It is consistent, coherent, emergently productive, and thus somehow unified. This could be seen as commensurate with strategies in the philosophy of religion aimed at grounding causal patterns and modal truths in the sovereign divine nature with its divine powers (e.g. Leftow (2012), and the use of observations about order, chance, and occasionalism in design arguments more generally). What is essential for this Indian argument is that coherent hardwiring into reality is itself seen as evidence of something that universally grounds the structure of the world. Arguably it is this feature (more than personhood, which is universal neither in the Upaniṣads nor in the scholastic Vedānta schools) that is a universally essential ingredient for the divine in philosophical Vedānta.
The issue of explaining the appearance of persistent characteristics through temporal development was one of the greatest challenges to Buddhism. 13 As a critique highlighting the formal-cause-shaped lacuna in Buddhist metaphysics, it applied not only to the consistent order of empirical phenomena in the early Abhidharma phenomenalist school, but also to the consistent order of appearance in the idealist Yogacāra school, or the coherence of each superimposed interpretation of reality in the Madhyamaka antifoundationalist view: even for a non-realist position, ostensibly interpretation itself requires some stable sortal capacity on which the appearance of formal consistency can be based. Only a monism can offer a convincing ground for the coherence of 'the world', however that 'world' is metaphysically construed. Buddhists typically declared themselves unwilling to speculate on the matter, pushed the problem along by blaming samsara or prior influences, or sought wily ways to incorporate continuous causation by another name into their thought. The famed Madhyamaka anti-foundationalist Śāntarakṣita said that identity-continuity is indeed constituted by successive 'moments' related to each other as upādāna or material cause, and upādeya or material effect; but, he claimed, this is merely a form of material-wise 'causation' between separate moments, not the real thing. 14 Such philosophical work-arounds were not convincing to other schools. For the monists, the refusal of coherent causation showed that a Buddhist account was explanatorily incomplete in such a profound way that it would better fit with a different world than the one we observe.

The Complexity Argument: combined individuals, causes, and trajectories
Allied with this was what we will call the Complexity Argument, which argues that we cannot draw any convincing and consistent line between individuals, and so are left with a level of shared identity that co-constitutes them alla move that is also seen in some 'gunky' Western arguments against the determinate separability of things, as we will see. To make this point, Śaṃkara attacks the competing Indian pluralist view of identities as aggregates by raising 'Ship-of-Theseus'-like questions about what happens when one thing combines with or causally influences another, leading to the development of a new entity. The atomists would explain this as one aggregated cluster combining with or affecting another to make up the 'thing' that is the effect. But Śaṃkara tries to show how absurd it is, in such cases of complex constitution, to attempt to trace individual identities through changes of configuration from atom to atom, or aggregate to aggregate.
He asks how, on the atomist account of causation, 'is the effect, with its component substances, present in the cause with its component substances? Is the whole compound present in [all] the components, or in each particular part?' (ŚBSB 2.2.18). 15 We might ask whether the whole cow is present in all the constituent atoms, or which of the few atoms making up the tiny embryo correlates with the many atoms later making up the horns, or the udders, and the milk that flows from them. Which of the causal potencies in the salt, flower, or sugar crystals, go to make up which 'parts' of the new phenomenon called a cake? It seems that no clear line of constitution or causation can be traced.
This entails a wider critique of the idea that constitution by aggregate identities can do enough explanatory work, and it is one of the many places where Indian debates touched on the problem of emergent properties. The argument in BS 2. 2.18 highlights this, and also draws on the debate between Vaiśeṣika atomism and Abhidharma Buddhism over whether aggregates (e.g. bodies) should be taken as wholes, or mere bundlesa debate that is really about what the criteria are for a discrete identity. Vaiśeṣika had argued that what shows that something is a whole, and not just a bundle, is that it has novel powers not possessed by its parts; it thus affirmed the ontological significance of emergence. Śaṃkara further notes that even within a single aggregate there are distinct local teloi as evidenced in the development of localized functions within a single thing: If the complete whole abides in its totality in each part, then the composite whole possesses the capacity of all its effects, and from its being one, then by the horn the effects of an udder should be produced, and the effects of the back should also be obtained from the chest. But this is not seen to be the case. (ŚBSB 2. 1.18) 16 Here he highlights entanglement within any given entity where the combination of its constituent parts yields new forms that are themselves freshly complex in a novel way that does not clearly supervene on the original constituents. What seems to be intended here is the idea that 'fusion' emergence (Humphreys (1997)), in which a non-divisible new complex entity is generated, implies that the original constituents must have shared an underlying nature capable of manifesting in the new properties (Śaṃkara focuses on functions as a way to mark out individuals rather than properties here). A related criticism that it is absurd to claim that there is no particular cause for particular things arising (ŚBSB 2.2.26) shows Śaṃkara's insistence that a viable metaphysical explanation must be able to account for there being a specific causal train of influence leading to each thing. In short, there must be holistic dispositions grounded in some kind of unity, producing entangled effects across the emergence of the whole entityand by extension, across the whole of reality.
He also criticizes the idea that mereological aggregates can serve as an ultimate formal cause of a consistent effect, since consistency in the effect shows consistency in the cause: a consistently causal complexity requires some unified explanation in terms of a shared formal cause, so there would be a regress of the explanatory lacuna. Buddhists had attempted to explain complex phenomena in terms of other complex phenomena (explaining aggregated everyday objects in terms of 'cognitive delusion and other factors', avidyādi) ad infinitum, without ever reaching any fundamental level: [Buddhist:] . . . may it not be that when cognitive delusions (āvidya) and other factors go on endlessly revolving like a water-wheel of pots, as the cause and effect of each other, a combination of things, emerging from that momentum, 17 becomes a possibility?
[Vedāntin:] that cannot be so. Why? Because of efficient causation's specificity of arising. It could be the case that a combination may arise if any efficient cause for the combination could be ascertained; but as a fact, it cannot be ascertained. For although cognitive delusions etc. may be the basis for one another, the earlier ones would still be the specific efficient cause of arising only to the later ones. That may be the case, but there is no cause of the arising of the combination. (ŚBSB 2.2.19, There are various ways to read this passage. One is as a simple observation that any attempted metaphysical picture where aggregates do all the causal work without bottoming out in any predisposed grounding entity incurs a regress since we cannot identify anything that shapes the aggregates. Another reading, focused on the analogy of a constantly turning water wheel, might see the Buddhist as arguing that the constant play of aggregates in mutual causal relations might be able to explain new phenomena; as Jonardon Ganeri puts it (in describing certain processual philosophies of mind), this would 'rest on the idea that dynamical systems of sufficient complexity can exhibit new properties, emergent macro-properties' (Ganeri (2012), 43). This speaks to the generation of emergent phenomena out of dynamic systemsa typical Buddhist way of explaining consciousness. But here there is still no causal explanation for the arising of the process as a whole. Śaṃkara acknowledges that it might emerge from the random, chance effect of the diverse dispositions of the constituents, but presses the point that continuous consistent coherence in a complex system can no longer be chance; it must be taken as dispositional. Otherwise, the effects would change randomly as the unconstrained different possible combinations of the complex base occurred. Coherent patterns of aggregation imply an underlying base that spans the whole range of coherence. This is true even if there is no basic level: any complex group of separate individuals with no shared nature would have unconstrained possibilities of combination, meaning that that what emerges from them would be chaotic. If, alternatively, they have the same nature, then they would consistently generate the same effects and we would have a static single-state universe. The only alternative that could explain the evolving consistent complexity we see in the world in terms of a combination of constituents would have to acknowledge that they have a shared dispositional structure that is complex yet coherent, and remains so through time. Thus, the attempt to explain things in terms of mereological complexes throws us back on the coherence argument. Śaṃkara points to these arguments here: how much more besides, friend, is this the case [that combinations cannot be the ultimate cause of other combinations] in assuming momentary atoms without an experiencer and devoid of a foundation. Here, if the intention of this is that ignorance and the rest are the cause of the combination, then how could that very thing be the grounded essence (āśrityātman) when it would have to arise from that combination? Or if you think that the combinations themselves recur constantly from the beginningless train of cause and effect (samsara), and cognitive delusion etc. are grounded in them, even then, when from one combination another emerges, it would either be regularly similar, or randomly be similar or dissimilar. If regularity be admitted, then a human body can have no possibility of being transformed into divine, worldly, or hellish bodies. 19 And if irregularity be admitted, then a human body may momentarily become an elephant, or be transformed into a god or back into a human form again. But both views contradict your position. (ŚBSB 2.2.19) 20 In these objections Śaṃkara implies (a) the requirement that pluralism be able to trace discretely plural causal lines for any grounding entities (an attack aimed at Vaiśeṣika atomism), (b) the idea that any complex must have a shared disposition if it consistently yields coherent causal results (an attack aimed at Buddhist mereology), (c) that shared dispositions in pluralities always demand a unified cause, since any plural cause will itself require such an explanation and incur a regress. We can see that these arguments build on some of the same intuitions as the coherence argument. But they also point to the phenomena of recombination and reunification as evidence that entities are not merely unified in their foundation, but also in their later manifestations complex patterns and new emergent fusions. Thus, this monism seeks to describe the diverse world not merely as a prior foundation which has become divided, but as a unity that lies at the origin and re-emerges repeatedly. Insofar as the world is a variably configured aggregate of parts, then there must be a single complex-but-entangled disposition explaining the whole, that underlies it.

The Connection Argument: a medium of causation and connection
This series of comments segués into an argument that things which are mereologically combinable must have some connecting medium. Śaṃkara suggests that the wholly separate components that make up things in the Vaiśeṣika view would need to be connected by some continuous medium of which they are a part. Vaiśeṣika had argued that there are real discrete inherence atoms that have the special character of combining other kinds of atomic entities together. But many found this unconvincing and proposed various alternative candidates for this plurality-connector: a shared abode or field that enables interactions, or the cognitive constructions of an idealistic 'experiencer'.
Critics of Vaiśeṣika atomism had questioned how inherence relations are able to get a grip on the individuals and connect them into a continuous reality (2.2.12) since the individuals, having no subsidiary parts, are either wholly connected (in which case they essentially coincide) or are not connected at all (2.2.12); Or if they have their own parts so they can be partially connected then a regress of the argument occurs. The notion of mereological linkage itself, as something that could span genuinely separate things without having a shared medium, is brought into question. The goal of this was to reveal that an ontology of separate individuals is conceptually unsuited to the world of experience, which reveals as much sameness and continuity as it does separateness and difference. The very issue of connection (inter-combinability, causal influence, common dispositions, co-emergences, and extensional measure) dissolves the cogency of the boundaries of the parts. In Theodore Sider's terms, the 'joints' between simple components no longer seem natural. Further, for the pluralist there seemed no way to distinguish between natural inherence relations signalling an entity and artificial conjunction relationsand relatedly, between intrinsic and extrinsic properties. All are of equal ontological status since only the parts are basic (2.2.13). Śaṃkara gives the example of persons and numbers being describable in multiple ways so that we cannot rely on an intuitive guideline for individuation. We are pushed ever again in the direction of monism.
Even Buddhism's Hume-like claim that patterns 'just happen' seemed to require some structural medium. What would enable momentary phenomena in flux to display a continued orientation? What anchors properties each to their respective locus so that they do not occur randomly? What is the basis of contrast and similarity? One can see why the Brahma Sūtras and Śaṃkara go on to discuss whether we should attribute actual existence to 'space' or ākāśa. Vaiśeṣika maintained a special role for space as a kind of geometric extensional matrix within which the substances, properties, actions, similarities, and distinctions of the empirical world could sustain a stable interrelationship; the abstract geometry of space facilitates the one-and-separateness (eka-pṛthaktva) of the world (see Vaiśeṣika Sūtras 2.2.31). Śaṃkara gives the example of a bird flying across the sky: how would we tell it is moving if there weren't some platform that facilitates specificity by acting as a placeholder for properties. It is space, here conceived as a field on which spatio-temporal locations are plotted, that allows us to see where a bird is flying, and where it is not. The Brahma Sūtras simply say 'And [this is shown] from the unqualifiedness of space' (ākāśe cāviśeṣāt; 2.2.24). Śaṃkara develops this as follows: [Vedāntin:] . . . you would say that ākāśa is merely an absence of obstruction, so when any one bird flies in space, there is the presence of obstruction (and so absence of space); hence another bird that may try to fly (there) will find no scope for doing so.
[Opponent:] It will fly where there is no obstruction.
[Vedāntin:] In that case, that very thing with the help of which 'the existence of an obstruction' is specified will itself be the positive (substantial or grounding; vastu) entity ākāśa and it will not be a mere absence of obstruction . . . Thus it is not correct to say ākāśa is insubstantial. (ŚBSB 2.2.24) 21 After putting his arguments for monism in terms of (a) the need for some persisting causal factor across change, (b) the difficulty of individuating composite entities, (c) the necessity of a connecting medium, this new development of the argument turns away from defining its monism in terms of material or efficient 'causation' towards refining the formal cause 'coherence' argument in terms of some consistent field that simply provides a placeholder for loci of appearance. This relates to Śaṃkara's argument in the commentary to 2.2.18 that the non-existence of a thing before it appears is incoherent because any limit or locus of non-existence is incoherent. It seems that on this account we are always talking about which forms of the One conditioning substrate are actualized in any given spatio-temporal point or vector of change. Yet all are always present in some sense. There is not scope here to explore the considerable implications of this shift towards thinking about existence less as a material, and more as a grid for possible forms appearing in relation to each other here. Suffice it to say, for now, that this is one of the directions of analysis that pushed Vedānta away from substantialistic conceptions of Brahman towards more abstract ones that saw specific entities as constraining configurations of a semantic field of possible forms, and Being per se as that structuring field of potential forms in which each 'thing' finds its ordered, world-constituting locus in relation to all others.
Rich monism: the supercausal, complex-simple, divine one What these arguments were meant to show is that if things were plural all the way down to the roots then the universe would be a disordered and wholly randomized chaos. Relative continuity, whether across space, time, particles, empirical appearances, or thoughts, would not exist. Cognitively, no inductive generalizations across context would be possible, with all the conventions of thought and language (including 'objects') that they make possible. Nothing would be differentiated and nothing could combine. When these arguments for a shared medium and cause were combined with 'efficient cause' arguments for a basic stuff capable of prompting the world's unfolding (made vis à vis Sāṃkhya's idea of inert prime matter), then Vedānta felt it had discerned a supercause of all things carrying within itself the potentia and pattern, the impulse and evolutionary template, for all reality now and to come. One can see why the spider emitting its elaborately patterned web was such an appealing metaphor; the image of a spider's web emphasizes the way that material, efficient, and formal causal powers must be wielded in unified concert by the single generating source. 22 In a sense, the satkāryavāda doctrine forced Indian metaphysicians to rethink the very notion that there must be a foundational level that is ontologically separate from the contingent manifestations it supports. It suggested that one should simply collapse all of a thing's subsidiary stages and future developments into the cause; for this reason Gerald Larson (1975) argued that satkāryavāda's idea of cause and effect are best understood in structural terms, and upadāna kāraṇa or 'material cause' is better translated as instrumentality or functional system. A transformation of the crude notion of a material substance flowed from this. The notion of materiality, previously drawn from tactile metaphors of malleable stuff like clay, metal or wood, was effectively de-substantialized and reduced to a simple pattern, template, or field of formation and constraint. This desubstantialization of Brahman might be seen to deflect any interpretation that treats Vedānta as a substantial monism, or even perhaps as 'existence monism'. 23 Further, the unified reality turned out not to have a single basic level, but rather describes a potentia-rich matrix for which no particular state, or level, is more basic. None could claim to be more ontologically fundamental since all of the temporally spread-out, evolved, complex, and emergent forms are equally present in the One as the successive moments of a larger disposition. When we see strings, particles, or atoms with our eyes, we should also 'see' dahlias, existential anxiety, and Prospero's conundrum of forgiveness with the inner eye of inference. Even if we do not immediately discern those possibilities, these are equally real. Thus, global satkāryavāda teases a collapse of all levels into the one scintillating, generative template.
How would this view sit in relation to contemporary philosophy's fresh wave of arguments for and against monism, which have emerged in the last decades? What we have called the Coherence Argument seems least well-represented in current literature, although the need for some cause or constraint explaining the developmental dispositions of things is implied in Schaffer's concern that a wholly pluralist ontology ought to produce a world that is 'modally unconstrained in composition' (Schaffer (2010), 40). The Complexity Argument shares some features with Schaffer's argument that 'the cosmos forms an entangled system' deserving of being treated as an irreducible whole in which there are no ultimate mereological parts (Schaffer (2010), 32). Zimmerman's argument for an ontology of 'atomless gunk' also shares with our Connection Argument the view that plural basic simples would not be able to account for the continuous, extended empirical world (see Zimmerman's (1996) argument focusing on the classic problem of deriving extension from dimensionless parts). Thus, whether they are valid or not, Śaṃkara's arguments need not be seen as too exotic for the modern metaphysician.
On the critical side, a relevant critique comes from Theodore Sider (2008), who considered a version of monism that treats the 'one' less as a medium or gunk than as a 'statespace structure', a formative structural field of constraints and relations shaping the subsidiary appearances of reality (ibid., 137). He allows that such a monistic statespace could accord with the everyday world (ibid., 134), but he rejects the value of such monist projects of explaining the common-sense world mapped in science. Books, bodies, and such things all have to be rephrased in a monist language as non-ultimate, non-natural fictions, for that monism to do any helpful work. Effectively Sider asks whether monism is sufficiently intuitive to fit our empirical experience, and whether the inference to a cause or medium that lies at the heart of the argument is warranted. Sider, echoing Bertrand Russell, found monism too counterintuitive to fulfil his common-sense naturalness requirement, committed as he wasand like so many analytic philosophersto the idea that the everyday language of his own familiar, modern, Western, science-informed way of thinking should be our guide to the real structure of the world. Some others have argued against such 'naïve commonsensical ontologies' and the epistemic assumptions on which they are foundednotably in favour of monism (see Horgan and Potrc (2007)). 24 Since Sider sees no advantages in monism, there is for him no reason to adopt its less intuitive scheme. But Vedānta's monist arguments try to (a) point to the way that monism accounts for the coherence, entanglement, and connections that pluralism does not, while showing that (b) concrete separate objects are no more intuitive building blocks of the world than coherences (waves, personal identities over time, analogies, generalities are all made of coherences), complexities (soil and such materials, biological beings, ships of Theseus are all made of complex entanglements that divide and combine), and connections (events, aggregations, comparisons, and space-time are made of connections).
A different direction of criticism might come from epistemological concerns about inferring causation that can be found in both Buddhist and Humean scepticism. The Coherence Argument is an argument from formal causation (it could be seen as part of the family of teleological arguments that are familiar to Western philosophers of religion). The Buddhists held, as did Hume, that we should not reify repeated patterns of correlation into principles or causes: this would be a purely speculative leap. Discussing the Vedāntic defence of inference to causes and grounds would take a separate article, but the Hindu Nyāya school of logic offers a hint: they argued that inference is so basic to our most basic cognitive activity that Buddhism's reluctance to explain causation seems like a refusal to do philosophy at all. Buddhists seemed to performed a hypocritically thin commitment to brute non-explanatory phenomenalism; hypocritical because its most basic reasoning involved using inference of the very kind it disavowed, and thin because it acknowledged a mysterious principle of constant correlation (Buddhism's pratītya samutpāda) or attributed formal dispositions to past experience (samsara) but refused to speculate on the ontological nature of such things, despite having used them to prop up their account.
Pluralism thus seemed to fail as a metaphysics, and scepticism thus seemed to fail as a cognitively consistent response to the world. But a number of questions remained. One was the substantivity of the monism produced by these arguments. If the argument succeeded then, what after all, had it shown? Is this 'one' merely the sum of all separate past, present, and future existing things reconceived as a 'whole', or does it display any marks of existence over and above those appearances it is invoked to explain? Should the idea of 'existence' or 'reality' even be applied to these conceptions of a medium, formal cause, or a statespace constraint that is more like 'spacetime' than a distinct substance (see Schaffer (2009)). Given the multiple meanings of Sanskrit terms for material cause, foundation, or grounding base (e.g. see Szanyi (2021) on āśraya), further work is needed to unpack what philosophers might mean by such a formative ground.
This relates to meta-ontological questions about when we should feel justified in reifying something. Both early Vedāntic and Sāṃkhya arguments for a universal substrate had required that we can identify properties that persist across all the subsidiary changes (the shine of gold, regardless of the change in form), revealing something continuous. In the case of clay statues and pots one can point to a persistent characteristic ('clay-ness') justifying the inference to something lying underneath the contingent forms. But in the case of all reality . . . what would it be? The quality of 'Being' (sat) itself, as the Chāndogya Upaniṣad suggested? Vedānta came to assert variously that being, consciousness (cit, which could be interpreted as either actual subjective awareness or as intelligibility), pervasion (vibhu), self-arising (svayambhu), and grounding (adhiṣṭhāna), and enjoyment were all core properties of the foundational reality of Brahman. But are these just synonyms for the generalized idea of existence? Further, in Schaffer's (2010, 3) terms, if this is a real unity, is it situated at a 'level' in the hierarchy of beings at which we can speak of the continuous element being prior to the plural parts rather than just an aspect or epiphenomenon? Assessing what these arguments are trying to argue for involves a number of what we might call meta-metaphysical debates about the nature of entityhood, grounding, causation, and ontological commitment.
A critic might object that the 'monism' demonstrated is really just a form of questionbegging, restating the same coherent, world-spanning, entangled pattern of empirical phenomena (cloaked in the guise of a single entity or ground) that it took as its evidence. It would then be not a refutation of other arguments such as pluralism, but an observation that even pluralisms acknowledge some unified feature of things. Yet an acknowledgement that it may be patterning of behaviour that matters in mapping out levels, rather than mereological constitution of more and less basic entities, can be found in Rueger and McGivern's argument that hierarchies concern levels of behaviour, not of entity. 25 This implies that, regardless of whether we call it a pluralism or a monism, the real granularity of existence concerns patterns, not things.
There is not scope in the present article to explore these concerns further, but it is important to acknowledge that these arguments are not necessarily seeking to describe a single existent thing in the senses we usually apply to the space-time concrete objects of the world. This was acknowledged by many of India's monist thinkers, for almost all of whom concepts, empirical data, the analytic functions of the mind, and emotional responses, as well as matter, were all part of 'reality'. The One envisioned here is not a space-time object of some conventional kind; rather the range of Vedāntic accounts of Brahman reflected its project of 'conceptualising different types of ontological relation' that we might apply to the whole and its parts (Frazier (2014), 15). The monist linguistic philosopher Bhartṛhari, for instance, claimed that the medium and structuring factor in all things is the abstract form of 'language' (śabda), which is 'active at every level of manifestation and is shared by all entities (from the highest . . . "Brahman"to the lowest)' (Ferrante (2015), 62; see also Ferrante (2013)). Others saw Brahman as pure agency possessed of powers (śakti) and instruments ( prakāra), or a mere 'seat' on which things depend (āśraya) or a field (kṣetra) of phenomena, manifesting with varied limiting constraints (upādhi). Such ideas, developed in scholastic terms during Vedānta's flowering in the subsequent centuries, aimed to improve upon the old notion of substance with something that might feasibly be at one time both ontologically independent and innately generative.
One question the philosopher of religion might ask is whether this account describes something more than the materials and fields of physics: is this anything that we might reasonably consider divine? There is not space to explore fully the diverse criteria that different traditions, Western and Indian, used to arbitrate the notion of 'divinity'. But the characteristics of being (a) self-sufficient and self-grounding and (b) all-creating and all-grounding, together formed complementary sides of a key Indian philosophical understanding of the divine. Vaiśeṣika atoms, Buddhist dharmas, the Sāṃkhya duality of matter and consciousness, were all claimed to ground their own existence (that is, they were generally not seen as dependent on other things, or at most, the dharmas might ground each other). But they did not quite cause their own formal evolution (as we have seen atoms needed an orderer, dharmas were subject to the mysterious pattern of pratītya samutpāda, and in Classical Sāṃkhya the prime matter (prakṛti) needed the impetus of pure consciousness or puruṣa, and the unexplained imbalance of the elements to evolve). Thus, a key factor in Vedānta's differentiation of the divine Brahman from the non-divine materials of other schools seems to have been its self-evolving, selfstructuring, supercausal status. One is tempted to say that here, as Kleeberg (2007, 558-559) says of Haeckel's German monism, that 'God = The Law of Causalityan immanent version of divine providence . . . the total of all powers and hence of all matter '. Monism, with the related position of pantheism, is often accused of being naturalist materialism in disguise. But Brahman was not some stuff pushed along by accidental forces to build up into contingent happenstance forms, like water molecules accidentally accreting into snowflakes, or snowflakes into a storm that accidentally accumulates an icy drift. The point of a monism based on global satkāryavāda was that such a view of accidental development is mistaken in its conception of 'chance'. The cold that catalyses icecrystals, or the wind that blows about the snowflakes, are different from the snow they affect. But when we are trying to account for the whole of reality then the factor that introduces 'chance' must be understood as part of the system to be accounted for. We might term this a rich monism, rather than what Schaffer calls a mono-levelled priority monism with little or no internal complexity and dynamism. Indeed, to their list of divine attributes, many of the Vedāntic monists added the characteristics of being pūrṇa or full, and possessing all forms and all potencies (sarvarūpa and sarvaśakti). The subtle spider that can weave a vast and exquisite structure from its own internal resources, the lake in which the waves and currents are not 'other' than the water, and the multifaceted diamond that hosts a spectrum of colour 'in' itself by virtue of its very structure: these were signposts to the structure of reality for monists in this tradition.