Book review: Systematicity: the nature of science, by Paul Hoyningen-Huene

What is science? It is somewhat frustrating for a scientist to not be able to answer this question precisely. Yet it is a very important question, in particular in the public debate. For example, how are we to convince people to listen to science if we cannot explain what is special about science? What makes science better than the opinion of any given person or institution?

Naturally, this has been a central question in philosophy of science. For a while, it was thought that science is characterized by a particular method, a set of rules that one can follow to produce new truths about the world. This is impossible, because for any finite set of observations, there is an infinite number of general propositions that agree with those observations. Then came Karl Popper: he proposed that a scientific proposition is a proposition that can in principle be falsified, that is, such that there exists a statement that would logically contradict it (whether it is actually true or not). For example, “all penguins are black” can be contradicted by the statement “this is a blue penguin”. Popper’s motivation was to distinguish between science and pseudo-science or religious discourse. For example, it is not possible to contradict the existence of God because any fact can be interpreted as what God wants.

Although still very popular today, in particular among biologists, falsifiability has been heavily criticized. There are several fatal shortcomings in this idea. A simple one is that it tends to classify pseudo-sciences as sciences, for a simple reason: they can be falsified because they actually have been falsified. So the criterion is not sufficient. Other arguments show that it is not necessary (or meaningful) either.

Other analyses have shown that methods used by scientists are rather flexible both historically and, more importantly, across disciplines. Physicists do not use double-blind tests with control groups. Paleontologists do not produce empirical knowledge by experimentation. So if there is a scientific method, then which one is it? It is not that there is no scientific method. Rather, scientific methods are objects of scientific activity (things that scientists develop, use and discuss) rather than definitions of it.

Paul Hoyningen-Huene proposes a new theory of the nature of science, called systematicity theory, which brings some interesting ideas to this question. It is published in a recent book, and formerly in a short article. First, the original angle is that instead of comparing science with pseudo-science, he compares science with everyday knowledge. With this perspective, it becomes clear that there is something special about not just natural sciences, but essentially all academic fields including human sciences. History, for example, is distinctly more scientific than anecdotes that you could tell at dinner.

The main thesis is that what characterizes science is that is more systematic than non-science (on a similar subject). This idea of systematicity is developed in several dimensions. It must be noted that his goal is descriptive, nor normative.

For example, scientific descriptions tend to be systematic, e.g. with taxonomy, axiomatization, periodization (for history). Take the recent discovery of actin rings in the axon of neurons thanks to super-resolution microscopy. This is purely descriptive. Is it not science because it is not a test of a theory, maybe on the epistemic level of a news article? No, it is clearly science: it is part of an effort to systematically describe what a cell is made of. Writing the state of the art in a thesis, for example, is an exercise to systematically cover everything relevant about a particular subject, and it is an important skill that a scientist must acquire. Not crediting and referencing a relevant study is considered a professional error.

A particularly important dimension of systematicity is the defense of knowledge claims, that is, the way scientific claims are backed up. In mathematics, for example, there is the formal proof, a systematic way of demonstrating the validity of a claim. In other sciences, one may try to systematically consider and rule out alternative interpretations. All sciences develop field-specific methods to avoid errors. It is not that there is a method that is guaranteed to produce truths. Rather, there is an effort in each discipline to systematically develop ways of tracking errors. This includes social practices, such as peer review. In peer review, the author must systematically address all contradictions raised by a reviewer.

The book addresses many other aspects. It is not a particularly entertaining book, in fact I suspect that the author has made a particular effort to be systematic in his treatment of the subject. But the thesis is interesting because it covers many distinctive aspects of science that are usually not reported when discussing the nature of science. It also gives a more satisfying account of how science differs from pseudo-science. Pseudo-science is typically selective rather than systematic: claims are supported by a careful selection of evidence; objections are dismissed rather than systematically rebutted.

Although the thesis is not meant to be normative, I think it provides an interesting perspective on several aspects of modern science that are currently discussed, and which are also relevant to the politics of science. I will briefly discuss two.

One is the spread of scientific story-telling. In so-called “high-profile” journals, in particular in biology, there is considerable pressure to present a “good story”, something that is coherent, appealing, entertaining. And as publishing in those journals basically determines whether you can remain a working scientist, this is considerable pressure on all scientists. A scientist must also be a good communicator, story-telling advocates say. Obviously, it is better to have a well-written paper than a poorly written paper. Yes, but everything else being equal. Here unfortunately making a good story means selecting and ordering results so as to construct a coherent narrative, while dismissing every observation, remark, or previous study, which weakens or confuses the narrative. This clearly goes against systematicity. What then distinguishes such scientific “stories” from pseudo-scientific claims misleadingly backed up by carefully selected facts? It seems clear that systematically acknowledging all facts and interpretations that are not in line with the thesis of the authors, or simply that require specific explanations, is critically important in a scientific study. Yes, it might make the paper less entertaining and exciting. But that should not be the primary goal: the primary goal a scientific paper is a systematic report on a study. Developing scientific writing skills does not necessarily mean making up stories.

Another and related aspect is the idea, in particular in the research funding system, that good science must be disruptive, paradigm-shifting - only innovative ideas must be funded. Yes, because it is better to do ground-breaking science than ground-scratching science. This is the key principle of the ERC, for example. But again, this is not what science is about. This might be what product development is about (not even sure about that). But science is about systematically consolidating, expanding and connecting existing pieces of knowledge. Occasionally extraordinary discoveries are made, or new fields emerge. But that is nowhere near the core of science, which relies on systematic, rigorous examination. Without this, what we are left with is a bunch of TED talks - entertaining, occasionally informing, but you cannot learn to build rockets by watching TED talks.

I do not think that systematicity theory exhausts the question, however. What seems missing, in particular, is that science is about telling truths about the world. Science is a systematic activity, but not any activity: it is an activity whose goal is to document truths about the world. This means that being a scientist is not just following some practices, but also making an ethical commitment: a commitment to an ideal of truth. This is in my view a critical point when discussing the politics of science - how science should be organized, evaluated, communicated.

While it certainly does not exhaust the subject, what is satisfying about Hoyningen-Huene’s book is that, while it is lucid enough to acknowledge that there is no universal scientific method, it still convincingly argues that there is something special about science, something that may be worthwhile.