E. J. Lowe

(1950 - 2014)

John Heil’s new book is remarkable in many ways. In a concise, lucid and accessible manner, it develops a complete system of ontology with many strikingly original features and then applies that ontology to fundamental issues in the philosophy of mind, with illuminating results. Although Heil acknowledges his intellectual debts to C. B. Martin, he is unduly modest about his own contribution to the development and application of this novel metaphysical system. A full examination of the position that Heil defends would require a book in itself, so I shall limit myself to discussing some of its central themes and to explaining a few doubts that I have concerning some aspects of it.

E. J. Lowe, a prominent figure in contemporary metaphysics, sets out and defends his theory of what there is. His four-category ontology is a metaphysical system which recognizes four fundamental categories of beings: substantial and non-substantial particulars and substantial and non-substantial universals. Lowe argues that this system has an explanatory power which is unrivalled by more parsimonious theories and that this counts decisively in its favour. He shows that it provides a powerful explanatory framework for a unified account of causation, dispositions, natural laws, natural necessity and many other related matters, thus constituting a full metaphysical foundation for natural science.

Recently, Terry Horgan and Matjaž Potrč have defended the thesis of ‘existence monism’, according to which the whole cosmos is the only concrete object. Their arguments appeal largely to considerations concerning vagueness. Crucially, they claim that ontological vagueness is impossible, and one key assumption in their defence of this claim is that vagueness always involves ‘sorites-susceptibility’. I aim to challenge both the claim and this assumption. As a consequence, I seek to undermine their defence of existence monism and support a common-sense pluralist ontology of ‘ordinary objects’ as being fully consistent with a thoroughgoing metaphysical realism.

Three different concepts of matter are identified: matter as what a thing is immediately made of, matter as stuff of a certain kind, and matter in the (dubious) sense of material ‘substratum’. The doctrine of hylomorphism, which regards every individual concrete thing as being ‘combination’ of matter and form, is challenged. Instead it is urged that we do well to identify an individual concrete thing with its own particular ‘substantial form’. The notions of form and matter, far from being correlative, are relatively independent. There is nothing absurd in the notion of form without matter. Matter provides neither a principle of individuation nor a criterion of identity for individual concrete things: their form alone provides both. Finally, a substance ontology which admits also the existence of particular qualities, or tropes, is to be preferred both to a substance ontology which denies the existence of tropes and to a pure trope ontology.

In the Second Meditation, Descartes famously asks at one point, ‘But what then am I?’ – to which his immediate answer is ‘A thing that thinks.’ It is this question, or rather the plural version of it, that Eric Olson examines in this excellent book. He thinks that it is – today, at least – a rather neglected question. He points out that it is wrong to confuse the question with the much more frequently examined question of what personal identity consists in. In fact, he thinks that possible answers to the two questions, even if not entirely independent of one other, constrain each other only to a rather limited extent. It is important to appreciate that Olson is not inquiring into what persons in general are, but only into what we human persons are. Olson explores all the major, and some of the less well-known, answers that have been offered to this question. He begins with the answer that he himself has defended in an earlier book, The Human Animal – the answer that we are human animals, that is, biological organisms of a certain kind. Indeed, Olson is, along with Peter van Inwagen, one of the best known ‘animalists’ – although he admits to being a little more tentative in his endorsement of this position now, for reasons that we shall come to later. The other views that he considers are these: that we are entities that are ‘constituted’ by, but not identical with, human animals (the view of Lynne Rudder …

Objects which philosophers have traditionally categorized as abstract are standardly referred to by complex noun phrases of certain canonical forms, such as ‘the set of Fs’, ‘the number of Fs’, ‘the proposition that P’, and ‘the property of being F’. It is no accident that such noun phrases are well-suited to appear in ‘Fregean’ identity-criteria, or ‘abstraction’ principles, for which Frege’s criterion of identity for cardinal numbers provides the paradigm. Notoriously, such principlesare apt to create paradoxes, and the most intuitively plausible ‘Fregean’ identity-criterion for properties is afflicted by this problem. In this case, it may be possible to overcome the difficulty by modifying the criterion in a way which requires an independent account of the existence-conditions of properties, but it appears that such a strategy demands acceptance of the doctrine of immanent realism—the view that a property exists only if it is exemplified by some object.

I propose a fourfold categorisation of entities according to whether or not they possess determinate identity-conditions and whether or not they are determinately countable. Some entities – which I call ‘individual objects’ – have both determinate identity and determinate countability: for example, persons and animals. In the case of entities of a kind K belonging to this category, we are in principle always entitled to expect there to be determinate answers to such questions as ‘Is x the same K as y?’ and ’How many Ks are there satisfying condition C?’, even if we may sometimes be unable in practice to discover what these answers are. But other entities apparently lack either determinate identity, or determinate countability, or both. In these terms I try to explain certain important ontological differences between familiar macroscopic objects and various rather more esoteric entities, such as the ‘particles’ of quantum physics, quantities of material stuff, and tropes or property instances.

In this innovative study of the relationship between persons and their bodies, E. J. Lowe demonstrates the inadequacy of physicalism, even in its mildest, non-reductionist guises, as a basis for a scientifically and philosophically acceptable account of human beings as subjects of experience, thought and action. He defends a substantival theory of the self as an enduring and irreducible entity - a theory which is unashamedly committed to a distinctly non-Cartesian dualism of self and body. Taking up the physicalist challenge to any robust form of psychophysical interactionism, he shows how an attribution of independent causal powers to the mental states of human subjects is perfectly consistent with a thoroughly naturalistic world view. He concludes his study by examining in detail the role which conscious mental states play in the human subject's exercise of its most central capacities for perception, action, thought and self-knowledge.