In a recent essay in this journal, John Maynard Smith argues that the often expressed idea that the genome is the repository of meaningful information is not merely a heuristically useful metaphor. Instead, he contends, it is a central idea in contemporary microbiology. While I am in general agreement with Maynard Smith on this issue, his account suffers, I believe, from using an inappropriate concept of ‘information.’ One result of this is that the concept of genomic information becomes burdened by (...) a conceptual load that the biological facts cannot support. When, however, the appropriate concept of information is used, then these burdens are shed, and the result is an account that is in substantial agreement with the heart of Maynard Smith's thesis. (shrink)

In many texts on evolution the reader will find a characteristic depiction of inheritance and evolution, one showing the generations of an evolving population linked only by a causal flow from genotype to genotype. On this view, the genotype of each organism in this population plays a dual role as both the motor of individual development and as the sole causal channel across the generations. This picture is known to be literally false. In many species, parents exert direct causal influence (...) on their offspring, and some of those influences cause the offspring to resemble the parent. For example, a butterfly that lays her eggs on the same plant host on which she hatched thereby exerts a causal influence on her offspring, and one apt to cause them to resemble her more than they would, had she chosen a plant of a different species. None of this is at all controversial, but it poses a puzzle. If the “Weissmanian” conception is literally false, why is it seen as a perspicacious representation of evolution? (shrink)

The genetic code has been regarded as arbitrary in the sense that the codon-amino acid assignments could be different than they actually are. This general idea has been spelled out differently by previous, often rather implicit accounts of arbitrariness. They have drawn on the frozen accident theory, on evolutionary contingency, on alternative causal pathways, and on the absence of direct stereochemical interactions between codons and amino acids. It has also been suggested that the arbitrariness of the genetic code justifies attributing (...) semantic information to macromolecules, notably to DNA. I argue that these accounts of arbitrariness are unsatisfactory. I propose that the code is arbitrary in the sense of Jacques Monod's concept of chemical arbitrariness: the genetic code is arbitrary in that any codon requires certain chemical and structural properties to specify a particular amino acid, but these properties are not required in virtue of a principle of chemistry. This notion of arbitrariness is compatible with several recent hypotheses about code evolution. I maintain that the code's chemical arbitrariness is neither sufficient nor necessary for attributing semantic information to nucleic acids. (shrink)

The use of informational terms is widespread in molecular and developmental biology. The usage dates back to Weismann. In both protein synthesis and in later development, genes are symbols, in that there is no necessary connection between their form (sequence) and their effects. The sequence of a gene has been determined, by past natural selection, because of the effects it produces. In biology, the use of informational terms implies intentionality, in that both the form of the signal, and the response (...) to it, have evolved by selection. Where an engineer sees design, a biologist sees natural selection. (shrink)

Inevitably, much of this reply will concern points on which I disagree with one or other of the commentators. I should start, therefore, by saying that I am delighted to find that their thinking is in many ways similar to my own, and that a serious attempt is under way to clarify the concept of information in biology.

Maynard Smith notes that he provides a natural history and not a philosophical analysis of the use of concepts of information in contemporary biology. Just a natural history, however rich, would do little to resolve the ongoing controversy about the role of these concepts in biology. None of the disputants deny that the biological use of these concepts is pervasive. The dispute is about whether these concepts—and the framework in which they are embedded—continue to be of explanatory value in contemporary (...) biology. Fortunately, Maynard Smith does much more than provide a natural history: his contribution is also a sustained attempt to justify many of the uses of information in biology. (shrink)

The central dogma of biology holds that genetic information normally flows from DNA to RNA to protein. As a consequence it has been generally assumed that genes generally code for proteins, and that proteins fulfil not only most structural and catalytic but also most regulatory functions, in all cells, from microbes to mammals. However, the latter may not be the case in complex organisms. A number of startling observations about the extent of non-protein-coding RNA (ncRNA) transcription in the higher eukaryotes (...) and the range of genetic and epigenetic phenomena that are RNA-directed suggests that the traditional view of the structure of genetic regulatory systems in animals and plants may be incorrect. ncRNA dominates the genomic output of the higher organisms and has been shown to control chromosome architecture, mRNA turnover and the developmental timing of protein expression, and may also regulate transcription and alternative splicing. This paper re-examines the available evidence and suggests a new framework for considering and understanding the genomic programming of biological complexity, autopoletic development and phenotypic variation. BioEssays 25:930-939,2003. (C) 2003 Wiley Periodicals, Inc. (shrink)

The semantic concept of information is one of the most important, and one of the most problematical concepts in biology. I suggest a broad definition of biological information: a source becomes an informational input when an interpreting receiver can react to the form of the source (and variations in this form) in a functional manner. The definition accommodates information stemming from environmental cues as well as from evolved signals, and calls for a comparison between information‐transmission in different types of inheritance (...) systems—the genetic, the epigenetic, the behavioral, and the cultural‐symbolic. This comparative perspective highlights the different ways in which information is acquired and transmitted, and the role that such information plays in heredity and evolution. Focusing on the special properties of the transfer of information, which are very different from those associated with the transfer of materials or energy, also helps to uncover interesting evolutionary effects and suggests better explanations for some aspects of the evolution of communication. (shrink)

The role played by the concept of genetic coding in biology is discussed. I argue that this concept makes a real contribution to solving a specific problem in cell biology. But attempts to make the idea of genetic coding do theoretical work elsewhere in biology, and in philosophy of biology, are probably mistaken. In particular, the concept of genetic coding should not be used (as it often is) to express a distinction between the traits of whole organisms that are coded (...) for in the genes, and the traits that are not. (shrink)

Maynard Smith is right that one of the most striking features of contemporary biology is the ever-increasing prominence of the concept of information, along with related concepts like representation, programming, and coding. Maynard Smith is also right that this is surely a phenomenon which philosophers of science should examine closely. We should try to understand exactly what sorts of theoretical commitment are made when biological systems are described in these terms, and what connection there is between semantic descriptions in biology (...) and in other domains. (shrink)

Through the use of such "folk" concepts as belief, desire, intention, and expectation, Daniel Dennett asserts in this first full scale presentation of...

Over the past three decades, the philosophy of biology has emerged from the shadow of the philosophy of physics to become a respectable and thriving philosophical subdiscipline. The authors take a fresh look at the life sciences and the philosophy of biology from a strictly realist and emergentist-naturalist perspective. They outline a unified and science-oriented philosophical framework that enables the clarification of many foundational and philosophical issues in biology. This book will be of interest both to life scientists and philosophers.

Is the history of life a series of accidents or a drama scripted by selfish genes? Is there an “essential” human nature, determined at birth or in a distant evolutionary past? What should we conserve—species, ecosystems, or something else? -/- Informed answers to questions like these, critical to our understanding of ourselves and the world around us, require both a knowledge of biology and a philosophical framework within which to make sense of its findings. In this accessible introduction to philosophy (...) of biology, Kim Sterelny and Paul E. Griffiths present both the science and the philosophical context necessary for a critical understanding of the most exciting debates shaping biology today. The authors, both of whom have published extensively in this field, describe the range of competing views—including their own—on these fascinating topics. -/- With its clear explanations of both biological and philosophical concepts, Sex and Death will appeal not only to undergraduates, but also to the many general readers eager to think critically about the science of life. (shrink)

The nature/nurture debate is not dead. Dichotomous views of development still underlie many fundamental debates in the biological and social sciences. Developmental systems theory offers a new conceptual framework with which to resolve such debates. DST views ontogeny as contingent cycles of interaction among a varied set of developmental resources, no one of which controls the process. These factors include DNA, cellular and organismic structure, and social and ecological interactions. DST has excited interest from a wide range of researchers, from (...) molecular biologists to anthropologists, because of its ability to integrate evolutionary theory and other disciplines without falling into traditional oppositions. The book provides historical background to DST, recent theoretical findings on the mechanisms of heredity, applications of the DST framework to behavioral development, implications of DST for the philosophy of biology, and critical reactions to DST. (shrink)

A historical and critical analysis of the concept of the gene that attempts to provide new perspectives and metaphors for the transformation of biology and its philosophy.