Summary: if you want to distinguish assemblages from aggregates in a flat ontology you need a metaphysics of emergence. But real emergence may not work unless we deny that parts of assemblages are separate from the whole. This seems to undermine the point of assemblages where, it is said, the parts are logically exterior from one another and can play elsewhere.
The idea of a flat ontology was taken over by Manuel Delanda from Gilles Deleuze. As Levi-Bryant notes in the Speculative Turn, it derives from the Deleuzean thesis of the univocity of being: viz that Being is always predicated of entities in the same sense (Bryant 2010, 269). A flat ontology is one in which no entity is ontologically more fundamental than anything else. Otherwise put, flat ontologies can be opposed to hierarchical ontologies:
[While] an ontology based on relations between general types and particular instances is hierarchical, each level representing a different ontological category (organism, species, genera), an approach in terms of interacting parts and emergent wholes leads to a flat ontology, one made exclusively of unique, singular individuals, differing in spatio-temporal scale but not in ontological status (DeLanda 2004, p. 58).
In a flat ontology the powers and dispositions of an entity are explained with reference to interactions between the particulars that compose or otherwise relate to it. It is never the result of entities of one kind being pushed around by a privileged being like a god, a transcendental subject, a natural state or its associated species essences (Sober 1980).
However, the behaviour of complex entities like organisms, people or societies must be more than the sum of their micro-interactions of these are to be genuine presences in the world and not accountancy tools for tracking the aggregate behaviour of their components. The macro-level properties of complex beings must thus be emergent from and not merely resultants of these interactions. Unless a concept of emergence can explain how complexes derive their powers from their parts without being reducible to their aggregate behaviour, it is of little value to a flat ontology. Similarly, as Graham Harman emphasizes in his commentary on Delanda, a flat ontology recognizes no ontological primacy of natural over so-called artificial kinds. Both kinds of kind should be viewed as having equal ontological weight to throw around (Harman 2008, 372).
The most widely accepted definition of emergence states that an emergent phenomenon cannot be predicted from its initial conditions (e.g. existence and microdynamics of precursor populations) short of running a simulation with relevantly similar properties (Bedau 1997, 378). For jobbing scientists, this definition of what is sometimes called ‘weak emergence’ usefully dodges philosophical issues about spooky emergent properties or downward causation. However, while unexceptionable and useful, the concept of weak emergence describes emergent behaviour as a function of our epistemic capacities and seems unable to account for genuine ontological novelty.
In Delanda’s work the requirement that the world contain non-derivative kinds or wholes is expressed as the distinction between ‘assemblages’ and ‘aggregates’. Delanda contrasts assemblages both with aggregates and with the synthetic wholes or ‘totalities’ postulated by idealist philosophers.
In a totality each part is constituted by logically necessary (interior) relations to the others parts. The Kantian object, for example, is constituted by the transcendental conditions of possible experience (space, time, the categories). The Hegelian master is constituted, as master, by his relationship to the servant.
An assemblage, on the other hand, is characterized by ‘relations of exteriority’: any part can be detached to ‘play’ elsewhere; though some parts (vital organs) may have a ‘contingently obligatory’ relation to the assemblage insofar as they or a functional equivalent may be required for its continued existence. A pig’s heart valve may have a contingently obligatory relation to a living pig, but this does not impugn its ontological independence; it does not, for example, prevent it being ‘xenotransplanted’ into the heart of a human donee (Delanda 2006, 11-12).
The properties of aggregates are resultants of the independent behaviours or properties of their parts. However, for Delanda, the macro-level properties actualized by assemblages depend also on interrelations between their parts and not only upon intrinsic properties and micro-behaviours:
The surface of a pond or lake may not afford a large animal a walking medium, but it does to a small insect which can walk on it because it is not heavy enough to break through the surface tension of the water. (Delanda 2004, 73; Delanda 2006, 11).
Delanda’s contribution to the Speculative Turn – ‘Causality, Emergence and Realism’ – clarifies, somewhat, the relationship between actualized or potential capacities and actualized properties:
Sharpness is an objective property of knives, a property that is always actual: at any given point in time the knife is either sharp or it is not. But the causal capacity of the knife to cut is not necessarily actual if the knife is not currently being used. In fact, the capacity to cut may never be actual if the knife is never used. And when that capacity is actualized it is always as a double event: to cut-to be cut. In other words, when a knife exercises its capacity to cut it is by interacting with a different entity that has the capacity to be cut (Delanda 2010, 285).
Aggregates are wholes whose global behaviour is the resultant of the individual behaviours of their parts and, for this reason, can often be predicted using the techniques of linear mathematics (as in the Fourier analysis of a periodic waveform).
However, in those systems Delanda calls ‘assemblages’ the higher-level behaviour will often not be deducible from the micro-behaviour of constituents even where, as in simple computer simulations like John Conway’s ‘game of life’, the dynamics of the components can be stated simply and exhaustively (Bedau 1997, 379-386). This is because higher-scale properties of assemblages catalyse and constrain the accessible behaviours of its constituents in ways that can’t be deduced from knowledge of their behaviour in isolation. A neuronal unit within an artificial neural network has the capacity to retain information about its past behaviour, but may only manifest this capacity in a recurrent network whose feedback modulates its input with its time-delayed output. The process enabled by the recurrent network determines the dynamics of the parts, though it also depends on the parts having functional properties relevant to neuronal behaviour. The emergent properties of the recurrent network depend on the relational properties of the whole network which allow the neuron to manifest a capacity for encoding a rudimentary history that it would not have manifested in a feedforward network.
Assemblages, for Delanda, thus exhibit macro-level emergent properties in virtue of their higher-level organization and structure. For example, higher-scale processes can shield components from chaotic influences that would disrupt coherent patterns or the sharing of information. This seems to be one of the mechanisms at work in Raleigh-Benard convection – a non-equilibrium system in which layers of fluid develop ordered convection cells when the temperature difference between the bottom and top of the layer reaches a critical value. According to Robert Bishop’s reconstruction of the mechanisms of emergence in Raleigh-Benard convection one of the ordering mechanisms here is a ‘shear flow’ caused by a critical Temperature gradient. The shear flow reduces the number of states accessible for an eddy within the fluid by causing ‘adjacent’ eddies to move in a common phase. This is equivalent to a reduction of thermodynamic entropy or increase in the correlatedness between events within the fluid (Bishop 2008, 239).
Bishop and other theorists of emergence like Jeffrey Goldstein argue that genuine ontological emergence occurs where the identities of components or levels are ‘confounded’ or ‘tangled’. One could object, like the emergence-skeptic Jagewon Kim, that if the parts of an assemblage are ontologically distinct then its ‘macro-level’ properties would be possessed in virtue of the properties and arrangements of its parts (the supervenience of macro-level properties on micro-level properties – Bishop 2008, 242-3). Arranging each part of an assemblage in a specific relation to its neighbours – as in the units of an artificial neural network – would suffice for the macro-level structures that generate the ‘surprising’ emergent behaviour exhibited in recurrent ANN’s. There would be no ‘downward’ causal influence from the assemblage itself since the micro-arrangement would already have fixed all the macro-level properties.
Otherwise put, if there is a supervenience of emergent macro-properties on micro-properties, then what appears as a top-down influencing of parts by the entity they compose is just an impressive bit of micro-puppetry. It follows that there would be no principled ontological distinction to made between assemblages and aggregates. There may be marked empirical differences of course, since what Delanda calls assemblages involve nonlinear interactions (whose equations of motion cannot be expressed as a linear sum of independent components) and these often lead to what Bedau calls weak emergence. But weak emergence is not enough to account for the ontological democracy of a flat ontology. It may be possible to buy real ontological emergence, of course, if we are prepared to accept that the parts of assemblages are not parts in the way that parts of aggregates are – that they are not distinct objects with independent properties or powers. But on this picture, assemblages begin to look spookily like good old bad old totalities!
Bryant, Levi (2010), in Levi Bryant, Nick Srnicek and Graham Harman (eds) The Speculative Turn: Continental Materialism and Realism (Melbourne: Re.press).
Bedau, Mark (1997), ‘Weak Emergence’, Philosophical Perspectives, 11, Mind, Causation, and World, pp. 375-399.
Bishop, Robert C. (2008), ‘Downward Causation in Fluid Convection’, Synthese 160: pp. 229-248.
Delanda, M. (2009), Intensive Science and Virtual Philosophy. London: Continuum.
Delanda, M. (2006), A New Philosophy of Society: Assemblage Theory and Social Complexity. London: Continuum.
Delanda, M (2010),’Emergence, Causality and Realism’, in Levi Bryant, Nick Srnicek and Graham Harman (eds) The Speculative Turn: Continental Materialism and Realism (Melbourne: Re.press).
Deleuze, G. (1994), Difference and Repetition, Paul Patton (trans.). London: Athlone Press.
Harman, Graham (2008), ‘Delanda’s Ontology: assemblage and realism’, Continental Philosophy Review 41, 367-383.
Sober, Elliot (1980) ‘Evolution, Population Thinking and Essentialism’, Philosophy of Science 47(3), pp. 350-383.