Research Areas - Plato


Marmodoro argues that Plato describes, albeit briefly, power structuralism in the Theaetetus; and she shows that this is a ‘novel’ type of power structuralism, different from contemporary versions.

It is of the greatest significance that in the relevant passage of the Theaetetus, Plato attributes a power structuralist theory broadly to his predecessors, as a general conception of reality that permeated their thought:


‘About this theory, we can assume the agreement of the whole succession of wise men, apart from Parmenides – not only Protagoras, but Heracleitus and Empedocles as well; and we can also assume the agreement of the best poets in each genre – Epicharmus in comedy and Homer in tragedy. When Homer spoke of ‘Oceanus, origin of gods, and mother Tethys’ he meant that everything is the offspring of flux and change.’ (152e2-8, added emphasis)


As Plato builds on the details of the theory it becomes evident that he is describing a power structuralist ontology (which is also an indication of the perspicuous understanding of structuralism in antiquity):


‘Nothing is hard, hot, or anything, just by itself, but in their intercourse with one another things come to be all things and qualified in all ways.’ (156e9-157a2, added emphasis)


The theory is described as a theory of flux, even of radical flux, which is invariably given a process-metaphysics interpretation by the commentators. Process-metaphysics is based on change, and involves some form of sequential alternation of properties. But qualitative succession need not be grounded on relational properties. Process-metaphysics is not structuralism. In contrast with the traditional reading as process-metaphysics, the applicant’s understanding of Plato’s description of the views of his predecessors takes his descriptions at face value:


‘It’s certainly no ordinary theory: it’s to the effect that nothing is one thing just by itself, and that you can’t correctly speak of anything either as some thing or as qualified in some way … The fact is that, as a result of movement, change, and mixture with one another, all the things which we say are… are coming to be; because nothing ever is, but things are ways of coming to be … Coming to be, and what passes for being, are produced by change, while not being and ceasing to be are produced by inactivity.’ (152d2-153a7, added emphasis)


Interaction generates being, namely properties such as being hot, hard, light, etc. Any of these generated properties, say P, has a being that is thoroughly determined by the relation that P has to the two interacting properties, P1 and P2:


‘In the case of the eyes, first, you mustn’t think of what you call white colour as being some distinct thing outside your eyes, or in your eyes either … Let us follow what we said just now, and lay it down that nothing is one thing just by itself [i.e. independently of interacting]. On those lines, we’ll find that black, white, and any other colour will turn out to have come into being from the collision of the eyes with the appropriate motion. What we say a given colour is will be neither the thing which collides, nor the thing it collides with, but something peculiar to each one [i.e. to the pair].’ (153d8-154a2)


Thus the identity of every property is defined by its relation to further (interacting) properties, and no property is what it is in virtue of itself. So every property is relationally defined and there are no categorical properties, namely properties with a primitive non-relational nature (and hence, non-powers). Furthermore, second order properties too are similarly defined relationally. A property P1 becomes an active or a passive power by interacting with another property P2. Here, apart from the property P which is generated by the interaction, each of the interacting properties P1 and P2 also acquires a second order property of being an active or a passive power. The second order property of P1, say, of ‘being an active power’, call it Q1, is exclusively defined in terms of the first order relations of interaction between P1 and P2:


‘Even in the case of those of them which act and those which are acted on, it isn’t possible to arrive at a firm conception … of either of them, taken singly, as being anything [i.e. an active or a passive power]. It isn’t true that something [P1] is a thing which acts [Q1] before it comes into contact with the thing which is acted on by it [P2]; nor that something is a thing which is acted on before it comes in contact with a thing which acts on it. And what acts when it comes into contact with one thing can turn out a thing which is acted on when it bumps into something else.’ (157a3-7, added emphasis)


So the theory described by Plato is a type of (actualist) power structuralism which explains first and second order properties structurally. The identity of a property P is defined, for its first order properties, in terms of its relations to the properties which generate P through their interaction, and for its second order properties, in terms of the relations P has to properties it interacts with.


In the Sophist Plato gives the definitive structuralist ontological criterion – of a world of just powers – by defining the real as causal power, and finding this a common commitment of the most disparate of the ancient ontologies:


‘I’ll take it as a definition that those [things] which are amount to nothing other than power.’ (247d-e, added emphasis)


His purpose is explicitly all encompassing of ancient world-systems, identifying the one commitment that unites even the most incompatible between them: the materialists and the immaterialists. Their common commitment is that the mark of the real is to be power; nothing but causal powers exist in ontology, whether this is an ontology of physical bodies (materialists) or an ontology of transcendent Forms (immaterialists). There are no aspects of reality which are non-powerful; its building blocks have no aspects to them which are inert.


(Anna Marmodoro, 2009)

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