John Barrow is increasingly recognized as one of our most elegant and accomplished science writers, a brilliant commentator on cosmology, mathematics, and modern physics. Barrow now tackles the heady topic of impossibility, in perhaps his strongest book yet. Writing with grace and insight, Barrow argues convincingly that there are limits to human discovery, that there are things that are ultimately unknowable, undoable, or unreachable. He first examines the limits on scientific inquiry imposed by the deficiencies of the human mind: our (...) brain evolved to meet the demands of our immediate environment, Barrow notes, and much that lies outside this small circle may also lie outside our understanding. Barrow investigates practical impossibilities, such as those imposed by complexity, uncomputability, or the finiteness of time, space, and resources. Is the universe finite or infinite? Can information be transmitted faster than the speed of light? The book also examines the deeper theoretical restrictions on our ability to know, including Godel's theorem--which proved that there were things that could not be proved--and Arrow's Impossibility theorem about democratic voting systems. Finally, having explored the limits imposed on us from without, Barrow considers whether there are limits we should impose upon ourselves. For instance, if the secrets of the atom are to be found only by recreating extreme environments at great financial cost, just how much should we devote to that quest? Weaving together this intriguing tapestry, he illuminates some of the most profound questions of science, from the possibility of time travel to the very structure of the universe. (shrink)

In the shadowy world between philosophy of science and ethics lie the paired concepts of underdetermination and incommensurability. Typically, scientific evidence underdetermines the hypotheses tested in research studies, providing neither proof nor disproof. As a result, scientists must judge the weight of the evidence, and in doing so, bring scientific and extrascientific values to bear in their approaches to assessing and interpreting the evidence. When different scientists employ very different values, their views are said to be incommensurable. Less prominent differences (...) represent partial incommensurabilities. The definitions and analyses provided by McMullin and by Veatch and Stempsey lay the foundation for the description of partial incommensurabilities in the current practice of assessing and interpreting epidemiologic evidence. This practice is called "causal inference" and is undertaken for the purpose of making causal conclusions and public health recommendations from population-based studies of exposures and diseases. Following the work of Bayley and Longino, several suggestions are examined for dealing with the partial incommensurabilities found in the general practice of causal inference in contemporary epidemiology. Two specific examples illustrate these ideas: studies on the relationship between induced abortion and breast cancer and those on the relationship between moderate alcohol consumption and breast cancer. (shrink)

This paper explores the relationship between concepts of probability and hermeneutics. It seeks to examine the relationship between subjective (Bayesian) views of probability and hermeneutic descriptions of understanding. It is argued that Gadamer'saccount of the prejudicial nature of understanding, derived from Heidegger'sanalysis of foreunderstanding, offers a provocative model of clinical reasoning. The implications of this model for evidence-based medicine are discussed in conclusion.