The usual way for new cells to come into being is by division of old cells. So the zygote, which is a—new—single cell formed from two, the sperm and ovum, is an exception. Textbooks of human genetics usually say that this new cell is beginning of a new human individual. What this indicates is that they suddenly forget about identical twins.

One of the ways of dividing all philosophers into two kinds is by saying of each whether he is an ordinary man's philosopher or a philosophers' philosopher. Thus Plato is a philosophers' philosopher and Aristotle an ordinary man's philosopher. This does not depend on being easy to understand: a lot of Aristotle's Metaphysics is immensely difficult. Nor does being a philosophers' philosopher imply that an ordinary man cannot enjoy the writings, or many of them. Plato invented and exhausted a form: (...) no one else has written such dialogues. So someone with no philosophical bent, or who has left his philosophical curiosity far behind may still enjoy reading some of them. (shrink)

A significant proportion of conservationists' work is directed towards efforts to save disappearing species. This relies upon the belief that species extinction is undesirable. When justifications are offered for this belief, they very often rest upon the assumption that extinction brought about by humans is different in kind from other forms of extinction. This paper examines this assumption and reveals that there is indeed good reason to suppose current anthropogenic extinctions to be different in kind from extinctions brought about at (...) other times or by other factors. Having considered – and rejected – quantity and rate of extinction as useful distinguishing factors, four alternative arguments are offered, each identifying a way in which anthropogenic extinction is significantly different from other forms of extinction, even mass extinction: (1) Humans are a different kind of natural cause from other causes of extinction; (2) Extinctions brought about by humans are uniquely persistent; (3) Anthropogenic extinctions are effectively random whereas past mass extinctions are rule-bound; (4) The impact of the current anthropogenic extinction event differs from the impact of other extinction events of the past, such that future recovery may not follow past patterns. Together, these four arguments suggest that the present-day extinction event brought about by humans may be unprecedented and that we cannot clearly extrapolate from past to present recovery from extinctions. Although insufficient as justification for the claim that present-day extinctions are undesirable, the arguments provide some ammunition for conservationists' conviction that species extinction – in which humans play an accelerating role – ought to be prevented. (shrink)

Knowledge of the ethical and legal basis of medicine is as essential to clinical practice as an understanding of basic medical sciences. In the UK, the General Medical Council requires that medical graduates behave according to ethical and legal principles and must know about and comply with the GMC’s ethical guidance and standards. We suggest that these standards can only be achieved when the teaching and learning of medical ethics, law and professionalism are fundamental to, and thoroughly integrated both vertically (...) and horizontally throughout, the curricula of all medical schools as a shared obligation of all teachers. The GMC also requires that each medical school provides adequate teaching time and resources to achieve the above. We reiterate that the adequate provision and coordination of teaching and learning of ethics and law requires at least one full-time senior academic in ethics and law with relevant professional and academic expertise. In this paper we set out an updated indicative core content of learning for medical ethics and law in UK medical schools and describe its origins and the consultative process by which it was achieved. (shrink)

This considerably revised second edition of Wittgenstein's 1914-16 notebooks contains a new appendix with photographs of Wittgenstein's original work, a new preface by Elizabeth Anscombe, and a useful index by E.D. Klemke. Corrections have been made throughout the text, and notes have been added, making this the definitive edition of the notebooks. The writings intersperse Wittgenstein's technical logical notations with his thoughts on the meaning of life, happiness, and death. "When the first edition of this collection of remarks appeared in (...) 1961 we were provided with a glimpse of the workings of Wittgenstein's mind during the period when the seminal ideas of the _Tractatus Logico-Philosophicus_ were being worked out. This second edition provided the occasion to be struck anew by the breadth, rigor, and above all the restlessness of that mind."—T. Michael McNulty, S. J., _The Modern Schoolman_. (shrink)

Based on the exactly solvable case of a harmonic oscillator, we show that the direct correspondence between the Bohr-Sommerfeld phase of semiclassical quantum mechanics and the topological phase of Aharonov and Anandan is restricted to the case of a coherent state. For other Gaussian wave packets the geometric quantum phase strongly depends on the amount of squeezing.