…and where to find it! Look no further than to this new paper on network analysis, forthcoming in Synthese, co-authored with Pitt Center friends.
Many scientists seem to agree with a favorite adage of the best film directors: “show, don’t tell”. A look at the latest articles in Nature will often reveal that half of the available space is devoted to pictures and diagrams rather than text. Supplemental materials may even consist exclusively or almost exclusively of diagrams.
While historians of science have long paid attention to visual representations, philosophers have by and large ignored them. But this is slowly beginning to change. In the last decade or so there have been recurrent bubbles of philosophical interest in diagrams, including a project directed by William Bechtel and Adele Abrahamsen at UCSD under the lovely acronym Worgods (Working Group on Diagrams in Science). While I was at the Pittsburgh Center with the two of them, I quickly recognized not only how important diagrams are in scientific practice, but also that they had figured prominently in much of my previous research. I had just never stopped to consider them as objects of inquiry in their own right.
Take this diagram as an example:
The figure appeared in a 1998 paper in Nature by Fire et al. It shows fluorescence micrographs of green fluorescent protein (GFP) in C. elegans. In a and b, GFP is expressed in a larva and in an adult, respectively. In d and e, the expression is suppressed. In g and h, the expression of GFP targeted to the nucleus is suppressed, but not the expression of GFP targeted to mitochondria. What is the point of figures like this one? In a forthcoming paper, I give a pretty straightforward answer. Many of the diagrams in your routine scientific publication depict what I call “causal contrasts”. They show what happens to a particular outcome variable if a specific intervention is performed, comparing this to a control in which the intervention is not performed. In the diagram above, the point is to show that an intervention with double-stranded RNA can suppress the expression of sequence-homologous genes (compare a and d, b and e). What is more, the diagram shows the specificity of this effect: if the double-stranded RNA is targeted only against the nuclear GFP gene, then the expression of mitochondrial GFP remains unaffected (compare a and g, b and h). For their demonstration of this extremely effective technique for gene suppression, the authors received the 2006 Nobel Prize in physiology or medicine.
I argue in the paper that many diagrams show causal contrasts, even though they differ significantly on the surface. Causal contrasts appear in many guises, some more obvious than others. They also appear in many scientific contexts, from the experimental to the observational to the purely theoretical.
Causal contrast diagrams are philosophically significant. They are a window into one of the key practices of scientific epistemology: causal inference. I suggest that this goes far in explaining why scientists, when reading a paper, turn to the diagrams first. A study’s key results can often be found there. Intriguingly, diagrams are often much more than merely a preferred representational tool for causal inferences. Diagrams themselves often constitute evidence: think of the ubiquitous photographs of electrophoresis gels in molecular biology, or the fluorescence micrograph shown above.
I call the paper “Spot the difference: Causal contrasts in scientific diagrams”. A preprint is available on the PhilSci archive, and the finished paper is about to come out in Studies in History and Philosophy of Biological and Biomedical Sciences.
The Philosophy of Historical Case Studies is now available as a volume of the Boston Studies in the Philosophy and History of Science. I co-edited the book with Tilman Sauer.
The title is bit of grammatical play: one can read the genitive “of” in two different ways. On the one hand, our interest is in the philosophy involved in studying historical cases — how to minimize bias in choosing cases, how to draw robust conclusions from them, how to adjudicate between different interpretations of the same case, and so on. On the other hand, however, we are also talking about the philosophy that emerges from historical case studies: many worthwhile questions in the philosophy of science are best answered (and perhaps only answerable) by looking closely and carefully at the past and present of actual science.
So the volume is part manifesto, part user’s manual, and part affirmation of a research program – we hope that many different kinds of readers will get something out of it.
It has been claimed that the integration of history and philosophy of science is nothing but a marriage of convenience. I think this is wrong — it is really a passionate romance, and I argue why in a recent co-written paper. Beyond a discussion of what is to be gained by integrated HPS in principle, we focus particularly on the methodology of integration in practice: how should we relate philosophical concepts to historical cases, and vice versa? Our penultimate draft is now on the PhilSci Archive.
The paper is forthcoming in a collected volume titled The Philosophy of Historical Case Studies, which was co-edited by Tilman Sauer and myself and will appear in the Boston Studies in the Philosophy and History of Science.
I gave a talk at the EPSA meeting in Düsseldorf on what I call the argument from the good lot (pdf). It uses a case study from genetics in the first half of the 20th century – how was DNA shown to bear hereditary information? – to argue that scientists work hard to avoid one of the great pitfalls of inferences to the best explanation: the bad lot.
I’ve uploaded the slides (pdf) to a talk I gave last week at a workshop in Oulu in Finland. This is my latest attempt to explicate the methodology of integrated history and philosophy of science (or at least of one type of such work). The workshop’s topic was “Testing philosophical theories against the history of science”, and the full program is well worth a look – it was a stimulating event.
A brief, German-language piece on the discovery that the bacterium Helicobacter pylori causes peptic ulcers is now online at Therapeutische Umschau.