Neutral Models in Biology (Eds) Matthew H. Nitecki and Antoni Hoffman Oxford University Press 1987 pp. 166 [ biology, philosophy of science ] _Neutral Models in Biology_ is a collection of eight essays on the use of "neutral" (or null) models in biology. While the title sounds rather narrow, the essays in fact raise and discuss broader issues within the philosophy of science. Here I discuss the essays in the order they come in the book, grouped in in sections titled "Molecular and Genetic Models", "Ecological Models" and "Palaeontological Models". In "Neutral Models in Molecular Evolution" James Crow gives an overview of the well known neutral theory of molecular evolution (which is probably the first theory that springs to mind when one mentions the word "neutral" in a biological context.) He doesn't make any explicit reference to work in the philosophy of science, but he discusses in separate sections the theory's predictive value, heuristic value, explanatory value and usefulness. Wimsatt's "False Models as Means to Truer Theories" is a broader look at the role of false models in science generally, illustrated by the development of the linear chromosome theory by the Morgan school around the 1920s. Most of what he says is applicable to broader science quite generally. In "Self-Organisation, Selective Adaptation, and Its Limits: A New Pattern of Influence in Evolution and Development" Kauffman models the genomic regulatory system as a network of Boolean switches. He presents the results of simulation studies which suggest that (under some fairly reasonable assumptions) there are generic statistical properties of such systems that may be largely "immune" to selective effects and so can be considered ahistorical universals. "How to be Objective in Community Studies" looks at the methodological (and metaphysical) difficulties involved in defining "ecological community". This is formulated within a more general philosophical background (with references to Goedel and Popper among others). The essay "On the Use of Null Hypotheses in Biogeography" by Paul Harvey is probably the most narrow (specific :-) of the essays, being a discussion of the use of Species x Island tables in searching for evidence of competitive exclusion. "Neutral Models in Paleobiology" uses neutral models to test explanations (or rather the need for explanations) for four different palaeobiological facts: the extinction of the trilobites, the periodicity of extinction events during the last 250 million years, the diversity of Ordovician faunas and evolutionary filling of morphospace in the coiling of Ammonoidea. In the first two cases the neutral model is rejected, giving some plausibility to alternative causal explanations, while in the third the sufficiency of the neutral model can be used to deny the need for an explanation. In the final case the construction of a neutral model appropriate for testing the hypothesis in question is not possible, but this in itself tells us something about the limitations of our knowledge. "Neutral Model of Taxonomic Diversification in the Phanerozoic: A Methodological Discussion" argues that the data are not detailed enough to decide between the neutral model and alternative periodic theories. "Testing Hypotheses or Fitting Models? Another Look at Mass Extinctions" is an essay by a statistician who has his own views on the use of models in biology. He sees himself as a "factory representative" selling statistical tools to customers, and his essay shows off some modern statistical methods in an analysis of the importance of mass extinctions relative to background extinctions. Along with all of this comes some general advice (and some warnings) about the use of statistical methods (including a warning about the unwarranted connotations of "neutral"). Even the most specialised of the essays is presented in such a way as to be understandable without any extremely technical knowledge. (All the essays do assume fundamental biological knowledge and basic statistical competence.) As a result the philosophical and methodological insights they have to offer are accessible to all biologists, and the essays that are broader in scope will also be of interest to scientists in other fields. The most impressive thing about the volume is the authors' philosophical and statistical/mathematical sophistication. They consider and use ideas produced by philosophers of science (Popper, Kuhn, Lakatos, Feyerabend, Duhem, Quine, etc. all get mentions) without subscribing themselves to any narrow conception of scientifoc method. Similarly they are happy to use statistical tools, but are always careful to consider their appropriateness and significance first. Danny Yee (danny@cs.su.oz.au) 28/7/93