_The Design Inference: Eliminating Chance Through Small Probabilities_ in the Cambridge Studies in Probability, Induction, and Decision Theory series, by mathematician and philosopher William Dembski is a fascinating book which lays out the case for the design inference attempting to show when such an inference is warranted. Dembski is currently a Fellow at the Discovery Institute, and this book was his dissertation for his doctoral degree in philosophy. The central question motivating this book is stated as "How can we identify events due to intelligent causes and distinguish them from events due to undirected natural causes?" The manner in which Dembski proposes this is done is through the design inference, which relies on uncovering intelligent causes by isolating the key trademark of intelligent causes: specified events of small probability. As Dembski shows in this book the applications of the design inference are widespread. Among other examples, Dembski considers the role of the design inference in forensic science, cryptography, the origins of life, the search for extraterrestrial intelligence, and parapsychology. Perhaps the most controversial application of the design inference occurs in the role of design in the origin of life. From this controversy, has arisen the debate between the standard Darwinian account of the origin of life and the account of life's origins given by the Intelligent Design Movement. Unfortunately, there are profound philosophical implications underlying this debate and this has led to the politicization of the debate itself. This is an unfortunate state of affairs because rather than allowing for the subject to be debated in a rational manner, the debate has instead moved into a state where each side engages in hysterics and attempts to slander the other side. However, if one wishes to understand this debate from an objective standpoint, this book is essential. Modern Western mainstream science has long waged a war on "the design inference" (since the time of Darwin), seeing in it an appeal to the supernatural. This has led to various domains which may make use of this inference (such as parapsychology) to be stigmatized and labeled as pseudo-science. However, as this book effectively shows, it is necessary to take a new look at the role of the design inference, free from the dogmatic tendencies ensconced in scientific orthodoxy. It should also be pointed out though that this book is highly mathematical in nature, and relies on probability theory to make its case. Following the mathematics may prove at times difficult for some.
In his introduction, Dembski considers the history of the idea of eliminating chance through small probabilities. One of the earliest instances of such an argument occurs in the writings of Cicero. But, later mathematicians and philosophers such as Laplace, Thomas Reid, and de Moivre appealed to this argument. From the history of science, a famous instance of the use of the design inference occurs when Ronald Fisher used it to show that Mendel's experimental results were falsified. Dembski also notes the role of this inference in the intelligent design debate. It should be pointed out that while noted Darwinists such as Richard Dawkins allow for the possibility of this argument, they maintain that in the case of the emergence of life the probabilities involved are not small enough. The mathematician Emile Borel was the first to state a version of the Law of Small Probabilities (what he called the "Single Law of Chance") as "Phenomenon with very small probabilities do not occur." However, there are difficulties with Borel's formulation, and a distinction must be made between patterns which are specified and patterns which are fabricated. As it turns out, the Law of Small Probabilities can be stated as "specified events of small probability do not occur by chance". What constitutes a "small probability" is another question, which was considered by Borel, and Dembski elaborates on such considerations. Another question for the design inference that occurs is what is meant by an "intelligent agent". Dembski then proceeds to give some examples of the design inference in the case of the legal system, forensic science, cryptography, and SETI. Following this, Dembski explains the design inference, proposing an explanatory filter which allows for one to determine whether an event occurs as a result of a regularity, chance, or design. Once the design inference has been written as an argument in symbolic form, the rest of this book will be devoted to showing that such an inference is valid and expounding upon the Law of Small Probability. In the case of the Creation-Evolution controversy, the design inference becomes a possibility. However, as Dembski shows the premise rejected by the evolutionist is either that "If Life is due to chance, then Life has small probability" or "Life is not due to regularity". To get around the first premise, evolutionists such as Dawkins may attempt to appeal to greater probabilistic resources, for example invoking the fact that one must consider the possibility that life can occur on any of all the planets in the universe or even the possibility of other universes and then invoking the Anthropic Principle (as Barrow and Tipler do). Some such as Kaufman have tried to get around the second premise by maintaining that life results from regularity and "crystallizes" at a phase transition. However, as Dembski successfully shows later in the book all of these approaches by evolutionists are problematic. Dembski then considers what is meant by intelligent agency. The next two chapters are highly technical and lay the groundwork for probability theory and complexity theory. Dembski explains Bayes' theorem, probability, background information, and likelihood. Following this, Dembski explains complexity, tractability, and randomness. In particular, applications occur in proof theory in a formal axiomatic system. Dembski also explains specification and detachability as well as prediction. Dembski then revisits the notion of randomness, showing how one can only know randomness from what it is not, and explaining the notion of Kolmogorov complexity. Following this, Dembski returns to the idea of small probability. Here, he explains what is meant by the idea of probabilistic resources. In particular, the evolutionist will attempt to invoke probabilistic resources (all the planets in the universe, the possibility of multiple universes, etc.) in his attempt to disallow the design inference. Dembski in particular regards attempts to appeal to multiple universes (or the "multiple worlds" of one interpretation of quantum mechanics or the "possible worlds" of philosophers) as being part of an "inflationary fallacy". Such notions defy common-sense and also an appeal to Occam's razor. Dembski ends by fully justifying the Law of Small Probability based on his foundational discussion in the past chapters. In the epilogue, Dembski argues against some of the criticisms that have been made of the design inference. In particular, it has been maintained that the design inference may amount to an appeal to the supernatural in certain cases (particularly as concerns the origin of life on earth and in certain instances in parapsychology). However, I believe this results more from a prejudice against the supernatural by scientists than any legitimate objection. Dembski also shows what is meant by coincidence (for example he considers the case of a coincidence which occurred to Carl Jung that he regarded as an instance of "synchronicity"). Finally, Dembski argues for the importance of information, maintaining along with Keith Devlin that "information should be regarded as . . . a basic property of the universe, alongside matter and energy (and being ultimately interconvertible with them)."
This is perhaps one of the most important books written on the issue of the design inference. The implications of this book are far reaching. And, if one hopes to understand the current debate over the origins of life on earth, this is essential reading.