Is Compartmentalization the Key to Modern Science?
A review of The Knowledge Machine: How Irrationality Created Modern Science, by Michael Strevens (New York: Liveright, 2020)
The Scientific Revolution stands as one of the most crucial developments of civilization. Centered in seventeenth-century Europe, it encompassed an explosion of discoveries about the natural world – discoveries in astronomy, physics, anatomy, physiology, and chemistry. Most importantly, a “scientific method” was developed, which focused on careful observation, experimentation, and the search for mathematical laws.
A fascinating perspective on modern science is presented by philosopher Michael Strevens in his book The Knowledge Machine: How Irrationality Created Modern Science. The subtitle’s controversial reference to “irrationality” is misleading; Strevens seems to mean something closer to “mental compartmentalization.” His book is highly readable and engaging, with numerous historical examples presented to illustrate the philosophic ideas.
Strevens sets out to answer two questions: Why is modern science so powerful, and why did it take so long to arrive?
Strevens notes that the ancient Greeks had a deep curiosity about the natural world, but their philosophizing was not particularly successful at scientific discovery (certainly not as compared to seventeenth-century Europe). Moreover, they lacked a method for resolving scientific disputes:
Physics after Aristotle bifurcated into two schools, the Epicureans and the Stoics, the one affirming an atomistic view in which the universe is composed of nothing more than particles careening blindly through the emptiness of space, other a view in which matter fills the universe according to the dictates of rationality… [T]he schools themselves remained detached intellectual traditions, separated by both their physics and their philosophy of life, until economic decline, barbarian invasions, and Christianity finished them off.1
So what made modern science so much more successful? Strevens argues that the key was a particular social convention which he calls “the iron rule of explanation.” This consists of:
The rule demanding that all scientific arguments be settled by empirical testing, along with … a definition of empirical testing in terms of shallow causal explanation, a definition of official scientific argument as opposed to informal or private reasoning, and the exclusion of all subjective and nonempirical considerations (philosophical, religious, aesthetic) from official scientific argument.2
For Strevens, a “shallow causal explanation” seems to mean a causal law or theory that is closely tied to the available evidence and does not rely on an elaborate metaphysical theory. He sees Newton’s law of gravitational attraction as a “shallow” explanation, in contrast to the “deep” explanation offered by Descartes’ theory of swirling vortices pushing objects downward.
Strevens’ appeal to “shallow” explanations seems to be his attempt to ground scientific theories in perceptual-level observations, and as such, it makes sense. In contrast to instrumentalists such as Ernst Mach who claimed that scientists can only produce descriptions of observational regularities (and who consequently denied the existence of atoms), Strevens emphasizes that scientists must offer causal explanations.
Strevens argues that the iron rule is so successful because it channels the energies of scientists toward productive observation and experimentation, and away from endless theorizing and speculation.
Why did it take so long to arrive? Because it is not “natural”; it requires a kind of mental compartmentalization, which is “irrational” because it tells us to disregard ideas in other areas of our thought, such as our ideas about beauty or religion or philosophy.
Strevens’ most valuable insight is his historical account of how the “iron rule” arose. He traces its origin back to the Reformation, which split Europe into warring religious camps, leading to a century of bloody and traumatic conflict. At the same time, nation-states grew in importance relative to religion. By the end of the Thirty-Years War in 1648, the main organizing lines of society had shifted:
The price of peace in Europe was a permanent bisection of the moral domain into nonoverlapping spheres of obligation, holy church and sovereign nation, each with its proprietary principles and its separate networks…3
[T]he divide between the public and the private was to a great extent normalized, to a great extant socially accepted. Public speech codes were made very clear and strictly enforced, yet not seriously expected to constrain private [religious] thought. The alternative – perpetual religious conflict – was too awful to countenance. This was the practical beginning of the modern liberal ideal of religious tolerance.4
This move toward partition can also be seen in Francis Bacon’s injunction to study “God’s Two Books” – the Bible and the Book of Nature – quite separately. Figures like Galileo and Boyle had “placed a bold wager on a narrowly-empirical form of inquiry.” Then when Newton continued this line of research, he “demonstrated the full potential of iron rule-governed science with a sweep and force that his contemporaries could not ignore.”5
Like many modern philosophers of science, Strevens is focused on the social aspects of science, not on the reasoning processes of individual scientists. His iron rule is “not a method of reasoning but a kind of speech code, a set of ground rules for debate.”6
Strevens seems to forget that the success of his iron rule depends on some crucial facts about the minds of individual scientists:
The ultimate base of knowledge is perceptual (i.e. observational).
Individual scientists can grasp perceptual facts of reality, and build conceptual knowledge based on their perceptions.
Individual scientists can make mistakes in forming conceptual knowledge.
For resolving disagreements and persuading others, scientists need ultimately to appeal to the perceptual knowledge of others.
This highlights another problem with Strevens’ analysis: he repeatedly denigrates philosophy as such – as something which the iron rule prohibits (along with considerations of religion and beauty). He does not seem to see the contradiction in a philosophical theory of science which says that scientists should disregard philosophy.
Strevens’ iron rule depends on an idea that has been widespread among philosophers of science of the last century (such as Karl Popper): the distinction between the “context of discovery” (considered “subjective” and not open to logical analysis) and the “context of justification” (considered public and therefore “objective”).
But does this division really make sense given the history of science? For many if not most scientists in history, it seems clear that their processes of discovery closely followed their observations – the same types of observations needed to justify their conclusions to others. The process of discovery often seems to follow a “logic of induction” which can be re-traced after the initial discovery, where this re-tracing constitutes a type of justification or proof.
Strevens’ “iron rule” does seem to capture something correct and important about modern science – notably the conviction that abstract scientific ideas must be grounded in observational facts and therefore such facts must be the basis for resolving scientific disputes. Stevens is right that the “iron rule” removed both ungrounded speculation and religion from science; coupled with a competitive and critical scientific culture, it has been extremely productive in rooting out errors and keeping scientists honest and focused on reality.
Michael Strevens, The Knowledge Machine: How Irrationality Created Modern Science (New York: Liveright, 2020), pp. 97-8
Strevens, p. 293
Strevens, p. 247
Strevens, p. 251
Strevens, p. 244
Strevens, p. 7