Plants produce a considerable number of structures of one kind, like leaves, flowers, fruits, and seeds, and this reiteration is a quintessential feature of the body plan of higher plants. But since not all structures of the same kind produced by a plant are identical—for instance, different branches on a plant may be male or female, leaf sizes in the sun differ from those in the shade, and fruit sizes can vary depending on patterns of physiological allocation among branches—a single plant genotype generally produces a multiplicity of phenotypic versions of the same organ. Multiplicity in Unity uses this subindividual variation to deepen our understanding of the ecological and evolutionary factors involved in plant-animal interactions. On one hand, phenotypic variation at the subindividual scale has diverse ecological implications for animals that eat plants. On the other hand, by choosing which plants to consume, these animals may constrain or modify plant ontogenetic patterns, developmental stability, and the extent to which feasible phenotypic variants are expressed by individuals. An innovative study of the ecology, morphology, and evolution of modular organisms, Multiplicity in Unity addresses a topic central to our understanding of the diversity of life and the ways in which organisms have coevolved to cope with variable environments.

What could the term multiplity mean for philosophy? Haas contends that modern understandings of the concept are either Aristotelian or Kantian. The Hegelian concept of multiplicity, Haas suggests, is opposed to both, or supersedes them.

In The Unity of Consciousness Tim Bayne draws on philosophy, psychology, and neuroscience in defence of the claim that consciousness is unified. In the first part of the book Bayne develops an account of what it means to say that consciousness is unified. Part II applies this account to a variety of cases - drawn from both normal and pathological forms of experience - in which the unity of consciousness is said to break down. Bayne argues that the unity of consciousness remains intact in each of these cases. Part III explores the implications of the unity of consciousness for theories of consciousness, for the sense of embodiment, and for accounts of the self. In one of the most comprehensive examinations of the topic available, The Unity of Consciousness draws on a wide range of findings within philosophy and the sciences of the mind to construct an account of the unity of consciousness that is both conceptually sophisticated and scientifically informed.

The quest for unity and multiplicity is one of the most important concerns in the history of human thought. Since the origins of the history of philosophy up to the present, we can observe more or less unceasing interest in the issue. The same holds of the writings of Thomas Aquinas, to whose conception this work is devoted. Since the problem of unity and multitude is closely linked to many other key metaphysical issues, such as the doctrine of transcendental concepts, the mode of composition of being qua being, as well as substantial and accidental being, or the doctrine of whole and part, we believe that its proper interpretation not only can clarify some partial metaphysical problem, but will also contribute to understanding the metaphysical thought of the Angelic Doctor as a whole.