University courses in natural science and courses in the social sciences or philosophy have a subtle difference:
Teachers in social science and philosophy courses often require students to read “classic primary works.” Philosophy teachers often assign Plato from two thousand years ago; social science teachers often assign Durkheim from a hundred years ago. In psychology, which only fairly recently began moving toward the natural sciences, teachers also often ask students to read Freud, William James, and Maslow.
Courses in the natural sciences, by contrast, almost never make such demands. Most science and engineering students at university have to learn special relativity and calculus, but university physics and advanced mathematics teachers never ask them to read the famous papers Einstein published at the beginning of the last century or Newton’s The Method of Fluxions and Infinite Series. In fact, even graduate students and scientists specializing in physics or mathematics have rarely read these original works.
David Deutsch writes in The Beginning of Infinity: “…In all the physics courses I took as an undergraduate and graduate student, not once did we study an original paper or book by one of the great physicists of the past. They would not even appear on the reading list. Only when a course dealt with a very recent discovery would we read the discoverer’s work. We do not learn Einstein’s theory of relativity directly from Einstein himself; as for Maxwell, Boltzmann, Schrödinger, Heisenberg and others, we know little more than their names. We encounter these pioneers’ theories in textbooks written by physicists, not historians of physics, and the physicists who wrote those books quite likely had not read the pioneers’ original works either.”
Why does this difference exist?
The answer can be approached from two angles:
1. Why do courses in the social sciences and philosophy need to assign classic primary works?
—I’ll leave this angle for you to think about (though the discussion below also answers it indirectly).
2. Why don’t courses in the natural sciences require classic primary works?
—This is the angle we’ll answer from.
This is how David Deutsch responds to the question in The Beginning of Infinity:
“Why? The immediate reason is that the original sources of these scientific theories are almost never very good sources. Why is that? Because every subsequent account is intended to improve on them, and some succeed in doing so. Improvements accumulate.”
This is the first reason natural science does not assign original works: after scientific theories are proposed, they are usually improved continuously, and those improvements accumulate. So you should read the latest interpretation of a theory.
“There is also a deeper reason. Someone who proposes an entirely new theory may initially still hold many mistaken ideas from earlier theories. They need to understand why those theories are defective, where their defects lie, and how the new theory explains everything the old theory could explain. But most people who eventually learn the new theory are concerned with something quite different. Usually they simply accept the theory as a matter of course, use it to make predictions, or combine it with other theories to understand some complicated phenomena.”
This is the second reason natural science does not assign original works: classic works in the natural sciences contain many “historical remnants”—debates with old theories, and so on—that are not what contemporary learners care about.
Finally, the most important reason of all is:
“When (contemporary) scientists learn a theory, they are not interested in what the theory’s originator … believed. When a physicist reads a textbook on relativity, the immediate goal is to learn the theory, not to find out what Einstein or the textbook’s author thought.”
In other words, a theory is independent of its inventor’s preferences and beliefs.
“Imagine that historians discovered Einstein had written his papers as a joke, or under threat of a gun, and that he was actually a lifelong believer in Kepler’s laws. That would be a strange and important discovery in the history of physics, and every textbook’s account of this aspect would have to be rewritten. But it would not affect our physics knowledge itself, and physics textbooks would not need to change at all.”
Contemporary philosophers need to study Plato’s original works painstakingly because they want to figure out what Plato was actually “thinking.” But contemporary physicists really do not need to know what Einstein was thinking at all!
“The reason scientists work hard to learn a theory, and the reason they care so little about fidelity to the original text, is that they want to know what the world is really like. Most importantly, that is also the goal of the theory’s originator. If it is a good theory—if it is an exceptionally outstanding theory, like the fundamental theories of physics today—then it will be extremely difficult to change it while keeping it a viable explanation. Therefore, when learners criticize the originators’ initial guesses, use the help of books, teachers, and colleagues, and seek viable explanations through these means, they will inevitably arrive at the same theory as the originators. This is how theories are faithfully passed down from one generation to the next, even though nobody cares in the least whether they are faithful.”
David Deutsch ultimately summarizes it this way in The Beginning of Infinity:
“Gradually, after many setbacks, the situation in non-scientific fields is also changing in this direction.”
Borrowing David Deutsch’s summary, I think that if one day psychology teachers no longer require students to read the classic primary works of Freud, William James, or Maslow, then psychology will have become thoroughly scientific.
Note
- This series of short popular-science and miscellaneous essays, Psychology New Knowledge Short Course, was written at the time to accompany the related content of Zhichao Wei: Psychology New Knowledge Course. It was published on the now-closed platform Fantuán. The original link no longer exists.
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