Causal and Informational Specificity in Biology

Janella Baxter (University of Pittsburgh)
The causal selection debate in the philosophy of biology literature has to do with the underlying justification for why biologists single out some causal variables rather than others in explanation. Loss of function studies are a central experimental approach to many areas of contemporary biology from which many gene-centered explanations are derived. Philosophers working on the causal selection debate have offered several accounts of what justifies the causal selection of genes in biological explanation -- namely, causal specificity and actual difference making. In this paper, I argue that neither view adequately captures the rationale for why biologists single out genes in loss of function studies. Causal specificity, as the literature has defined it, is not explanatorily relevant for loss of function studies and the actual difference making account cannot distinguish between actal difference making approaches researchers regard as illuminating from ones they don't. I offer a more nuanced account of the types of actual difference making techniques biologists employ in loss of function studies to better accommodate the causal reasoning at play in this area of research.
 

María Ferreira Ruiz (University of Geneva)
Against claims that, in biology, 'information' is used merely metaphorically, or that it cannot be rigorously accounted for, a very recent approach sets out to provide a rich, substantial concept of biological information by analyzing the information talk in biology in terms of causal specificity and the mathematical theory of communication. I examine what a substantial concept of biological information would be, and contend that no such concept follows from the framework. I discuss the grounds for claiming that the framework yields a substantial concept of biological information as opposed to some other concept, and the extent to which it yields a substantial concept of biological information, as opposed to an unsubstantial one. Rather than help vindicating the information talk in biology, it can be used to argue for (biological) information-eliminativism. Ultimately, key questions about the invocation of information in biological explanation remain open.

Oliver Lean (University of Calgary)
Recent work in the philosophy of biology has focused on "causal specificity" as a means of comparing the causal importance of genes versus other causal factors in development. In this paper, I aim to bring philosophical attention to a quite different sense of specificity - one that is almost certainly far more important to the study of biological processes at molecular scales. "Binding specificity", as I will call it, refers to the selectivity with which a biomolecule binds to a given target to the exclusion of others. I first outline the role this concept plays in the field of drug design, which explicitly aims to develop drug treatments that are highly specific in this sense, and which does so for clearly-defined purposes. I then apply the lessons learned to interpret binding specificity as a causal concept within the interventionist framework. More specifically, I interpret binding specificiy as a rationale for causal selection - the practice of picking out one or a subset of causes of an effect as "the" cause, or as being especially relevant. Since drug design explicitly selects between candidate drugs based on their specificity, this offers a clear and tractable case study for understanding causal selection. I find that, as well as serving directly practical goals such as the treatment of illness with a minimum of side-effects, molecules with high specificity are also valuable epistemic tools for understanding the causal structure of molecular processes.

Alan Love (University of Minnesota, Twin Cities)
Although philosophers have long compared the relative importance of genes to other causes, no consensus has emerged about whether the privileging of genetic causation in biological investigation and explanation is justified. However, little effort has been expended on understanding practices where scientists attempt to measure information or causal specificity. An example of this type of practice — measuring positional information in gene expression during pattern formation in Drosophila embryogenesis — shows that biologists are unconcerned with comparing the amount of information in genes with that of other factors and focused on whether the measured causal specificity explains the phenomenon under scrutiny.

Specificity-talk is pervasive in descriptions of molecular biological information, explanations of genetic causation, and arguments for and against the causal parity thesis in philosophy of biology. In my commentary, I consider the heavy epistemic and normative weight that has been put on the concepts of causal and informational specificity. Despite diverse accounts of informational and causal specificity that appear in the philosophical literature, there is no consensus as to what is the best account. I suggest that this failure of consensus may be the result of different metaphysical accounts of specificity, different methodologies, or different normative epistemological claims being relied upon by practitioners for different purposes.