The correct explanation of why species, in evolutionary theory, are individuals and not classes is the cladistic species concept. The cladistic species concept defines species as the group of organisms between two speciation events, or between one speciation event and one extinction event, or (for living species) that are descended from a speciation event. It is a theoretical concept, and therefore has the virtue of distinguishing clearly the theoretical nature of species from the practical criteria by which species may be (...) recognized at any one time. Ecological or biological (reproductive) criteria may help in the practical recognition of species. Ecological and biological species concepts are also needed to explain why cladistic species exist as distinct lineages, and to explain what exactly takes place during a speciation event. The ecological and biological species concepts work only as sub-theories of the cladistic species concept and if taken by themselves independently of cladism they are liable to blunder. The biological species concept neither provides a better explanation of species indivudualism than the ecological species concept, nor, taken by itself, can the biological species concept even be reconciled with species individualism. Taking the individuality of species seriously requires subordinating the biological, to the cladistic, species concept. (shrink)

When Charles Darwin published his theory in 1859 the biological community gave very different receptions to the idea of evolution and to the theory of natural selection. Evolution was accepted as widely and rapidly as natural selection was rejected. Most biologists were ready to accept that evolution had occurred, but not that natural selection was its cause. They preferred other explanations of evolution, such as theories of big directed variation, or admitted that they did not know its cause. Darwin himself (...) never maintained that natural selection was the sole cause of evolution. He thought of it as one among several causes, and did not specify how much evolution had occurred by the natural selection of fortuitous variations, and how much by other factors such as the inherited effects of use and disuse. However, Darwin did maintain that natural selection was in principle capable of explaining all the observed properties of organisms. He did not think that there were some characteristics that were particularly likely to have evolved by natural selection, and other kinds that were not. Against this, many of this critics thought that there were characteristics that natural selection was particularly powerless to explain. Thus it could not account for characteristics that were detrimental, or those that seemed useless (such as species differences), or those that were of too little importance for natural selection to have favoured them. There were also characteristics of such complexity that it was unimaginable that natural selection could have built them up in tiny stages from fortuitous, undirected variants. The present essay will be concerned with just one, the last mentioned, of these kinds of characteristics. (shrink)

This collection explores the impact of Richard Dawkins as scientist, rationalist and one of the most important thinkers alive today. Specially commissioned pieces by leading figures in science, philosophy, literature, and the media, such as Daniel C. Dennett, Matt Ridley, Steven Pinker, Philip Pullman and the Bishop of Oxford, highlight the breadth and range of Dawkins' influence on modern science and culture, from the gene's eye view of evolution to his energetic engagement in public debates on science, rationalism, and religion. (...) The volume includes personal reminiscences and critical debate as well as accessible discussions of science – it provides a stimulating tribute to a remarkable intellectual. (shrink)

An odd thing about people, compared with other animals, is that the more of us there are, the more we thrive. World population has doubled in my lifetime, but the world's income has octupled. The richest places on Earth are among the most densely populated.