David S. Oderberg

This paper re-examines some well-known and commonly accepted arguments for the non-individuality of the embryo, due mainly to the work of John Harris. The first concerns the alleged non-differentiation of the embryoblast from the trophoblast. The second concerns monozygotic twinning and the relevance of the primitive streak. The third concerns the totipotency of the cells of the early embryo. I argue that on a proper analysis of both the empirical facts of embryological development, and the metaphysical importance or otherwise of those facts, all three arguments are found wanting. None of them establishes that the embryo is not an individual human being from the moment of conception.

Organisms possess a special unity that biologists have long recognized and that cries out for explanation. Organs and collectives also have their own related kinds of unity, so what distinguishes the unity of the organism? I argue that only substantial form, a central plank of hylemorphic metaphysics, can provide the explanation we need. I set out the idea that whilst organisms possess substantial form, organs abtain the substantial form of the organisms they belong to, and collectives contain the substantial forms of their organismic members. I consider a number of difficult cases, including lichens, biofilms, cellular slime moulds, and plasmodial slime moulds, arguing that none of them pose a serious threat to the threefold distinction between organ, organism, and collective. I conclude by arguing that two prominent, alternative unity principles for organisms do not work, thus giving indirect support to the need for substantial form.

[About the book] Natural law theory says that humans can only live well if they recognise the goods that are natural for humans, and understand how those goods generate the system of practical guidance that we call morality. Natural law is a long-established and flourishing ethical tradition, with roots in Aristotle and Aquinas, which is increasingly recognised as a worthy competitor to Kantianism, utilitarianism and virtue ethics. The new essays in this collection represent the latest thinking - both constructive and critical - of some of the most important thinkers in the field. And they reflect the growing influence, sophistication, and importance of natural law theory within contemporary ethical debate.

In "personal and impersonal identity" ("mind", 1988) timothy sprigge discusses reasons for a general suspicion of trans-temporal identity, and rejects what he says are the usual grounds given against the suspicion, providing instead his own reasons for rejecting it. he concludes that trans-temporal identity, including personal identity, is as genuine a case of identity as what he considers to be the paradigmatic case of identity. in this brief note i take issue with some of the basic elements of sprigge's argument

The distinction between the essence of an object and its properties has been obscured in contemporary discussion of essentialism. Locke held that the properties of an object are exclusively those features that ‘flow’ from its essence. Here he follows the Aristotelian theory, leaving aside Locke’s own scepticism about the knowability of essence. I defend the need to distinguish sharply between essence and properties, arguing that essence must be given by form and that properties flow from form. I give a precise definition of what the term of art ‘flow’ amounts to, and apply the distinction to various kinds of taxonomic issues.