Upvoted! My discussion of a bunch of these things above is very breezy, and I approve of replacing the vague claims with more specific historical ones. To clarify, here are four things I'm not criticizing:

  • 1. Eliminativism about particular mental states, of the form 'we used to think that this psychological term (e.g., "belief") mapped reasonably well onto reality, but now we understand the brain well enough to see it's really doing [description] instead, and our previous term is a misleading way of gesturing at this (or any other) mental process.'

I'm an eliminativist (or better, an illusionist) about subjectivity and phenomenal consciousness myself. (Though I think the arguments favoring that view are complicated and non-obvious, and there's no remotely intellectually satisfying illusionist account of what the things we call "conscious" really consist in.)

  • 2. In cases where the evidence for an eliminativist hypothesis isn't strong, the practice of having some research communities evaluate eliminativism or try eliminativism out and see if it leads in any productive directions. Importantly, a community doing this should treat the eliminativist view as an interesting hypothesis or an exploratory research program, not in any way as settled science (or pre-scientific axiom!).
  • 3. Demanding evidence for claims, and being relatively skeptical of varieties of evidence that have a poor track record, even if they "feel compelling".
  • 4. Demanding that high-level terms be in principle reducible to lower-level physical terms (given our justified confidence in physicalism and reductionism).

In the case of psychology, I am criticizing (and claiming really happened, though I agree that these views weren't as universal, unquestioned, and extreme as is sometimes suggested):

  • Skinner's and other behaviorists' greedy reductionism; i.e., their tendency to act like they'd reduced or explained more than they actually had. Scientists should go out of their way to emphasize the limitations and holes in their current models, and be very careful (and fully explicit about why they believe this) when it comes to claims of the form 'we can explain literally everything in [domain] using only [method].'
  • Rushing to achieve closure, dismiss open questions, forbid any expressions of confusion or uncertainty, and treat blank parts of your map as though they must correspond to a blank (or unimportant) territory. Quoting Watson (1928):
With the advent of behaviorism in 1913 the mind-body problem disappeared — not because ostrich-like its devotees hid their heads in the sand but because they would take no account of phenomena which they could not observe. The behaviorist finds no mind in his laboratory — sees it nowhere in his subjects. Would he not be unscientific if he lingered by the wayside and idly speculated upon it; just as unscientific as the biologists would be if they lingered over the contemplation of entelechies, engrams and the like. Their world and the world of the behaviorist are filled with facts — with data which can be accumulated and verified by observation — with phenomena which can be predicted and controlled.
If the behaviorists are right in their contention that there is no observable mind-body problem and no observable separate entity called mind — then there can be no such thing as consciousness and its subdivision. Freud's concept borrowed from somatic pathology breaks down. There can be no festering spot in the substratum of the mind — in the unconscious —because there is no mind.
  • More generally: overconfidence in cool new ideas, and exaggeration of what they can do.
  • Over-centralizing around an eliminativist hypothesis or research program in a way that pushes out brainstorming, hypothesis-generation, etc. that isn't easy to fit into that frame. I quote Hempel (1935) here:
[Behaviorism's] principal methodological postulate is that a scientific psychology should limit itself to the study of the bodily behavior with which man and the animals respond to changes in their physical environment, and should proscribe as nonscientific any descriptive or explanatory step which makes use of terms from introspective or 'understanding' psychology, such as 'feeling', 'lived experience', 'idea', 'will', 'intention', 'goal', 'disposition', 'represension'. We find in behaviorism, consequently, an attempt to construct a scientific psychology[.]
  • Simply put: getting the wrong answer. Some errors are more excusable than others, but even if my narrative about why they got it wrong is itself wrong, it would still be important to emphasize that they got it wrong, and could have done much better.
  • The general idea that introspection is never admissible as evidence. It's fine if you want to verbally categorize introspective evidence as 'unscientific' in order to distinguish it from other kinds of evidence, and there are some reasonable grounds for skepticism about how strong many kinds of introspective evidence are. But evidence is still evidence; a Bayesian shouldn't discard evidence just because it's hard to share with other agents.
  • The rejection of folk-psychology language, introspective evidence, or anything else for science-as-attire reasons.

Idealism emphasized some useful truths (like 'our perceptions and thoughts are all shaped by our mind's contingent architecture') but ended up in a 'wow it feels great to make minds more and more important' death spiral.

Behaviorism too emphasized some useful truths (like 'folk psychology presupposes a bunch of falsifiable things about minds that haven't all been demonstrated very well', 'it's possible for introspection to radically mislead us in lots of ways', and 'it might benefit psychology to import and emphasize methods from other scientific fields that have a better track record') but seems to me to have fallen into a 'wow it feels great to more and more fully feel like I'm playing the role of a True Scientist and being properly skeptical and cynical and unromantic about humans' trap.

A simple sketch of how realism became unpopular

by Rob Bensinger 3 min read11th Oct 201953 comments


[Epistemic status: Sharing current impressions in a quick, simplified way in case others have details to add or have a more illuminating account. Medium-confidence that this is one of the most important parts of the story.]

Here's my current sense of how we ended up in this weird world where:

  • I still intermittently run into people who claim that there's no such thing as reality or truth;
  • a lot of 20th-century psychologists made a habit of saying things like 'minds don't exist, only behaviors';
  • a lot of 20th-century physicists made a habit of saying things like 'quarks don't exist, only minds';
  • there's a big academic split between continental thinkers saying (or being rounded off to saying) some variant of "everything is culture / perception / discourse / power" and Anglophone thinkers saying (or being rounded off to saying) "no".

Background context:

1. The ancient Greeks wrote down a whole lot of arguments. In many cases, we're missing enough textual fragments or context that we don't really know why they were arguing — what exact propositions were in dispute, or what the stakes were.

2. In any case, most of this is screened off by the fact that Europe's memetic winners were Christianity plus normal unphilosophical beliefs like "the sky is, in fact, blue".

3. Then, in 1521, the Protestant Reformation began.

4. In 1562, the Catholics found a giant list of arguments against everything by the minor Greek skeptic Sextus Empiricus, got very excited, and immediately weaponized them to show that the Protestant arguments fail (because all arguments fail).

5. These soon spread and became a sensation, and not just for being a useful superweapon. Plenty of intellectuals were earnest humanists used to taking arguments at face value, and found Sextus' arguments genuinely upsetting and fascinating.

I trace continental thinkers' "everything is subjective/relative" arguments back to a single 1710 error in George Berkeley:

[...] I am content to put the whole upon this Issue; if you can but conceive it possible for one extended moveable Substance, or in general, for any one Idea or any thing like an Idea, to exist otherwise than in a Mind perceiving it, I shall readily give up the Cause[....]
But say you, surely there is nothing easier than to imagine Trees, for instance, in a Park, or Books existing in a Closet, and no Body by to perceive them. I answer, you may so, there is no difficulty in it: But what is all this, I beseech you, more than framing in your Mind certain Ideas which you call Books and Trees, and the same time omitting to frame the Idea of any one that may perceive them? But do not you your self perceive or think of them all the while? This therefore is nothing to the purpose: It only shews you have the Power of imagining or forming Ideas in your Mind; but it doth not shew that you can conceive it possible, the Objects of your Thought may exist without the Mind: To make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest Repugnancy.

If I can imagine a tree that exists outside of any mind, then I can imagine a tree that is not being imagined. But "an imagined X that is not being imagined" is a contradiction. Therefore everything I can imagine or conceive of must be a mental object.

Berkeley ran with this argument to claim that there could be no unexperienced objects, therefore everything must exist in some mind — if nothing else, the mind of God.

The error here is mixing up what falls inside vs. outside of quotation marks. "I'm conceiving of a not-conceivable object" is a formal contradiction, but "I'm conceiving of the concept 'a not-conceivable object'" isn't, and human brains and natural language make it easy to mix up levels like those.

(I can immediately think of another major milestone in the history of European thought, Anselm's ontological argument for God, that shows the same brain bug.)

Berkeley's view was able to find fertile soil in an environment rife with non-naturalism, skeptical arguments, and competition between epistemic criteria and authorities. Via Kant and Kant's successors (Hegel chief among them), he successfully convinced the main current of 19th-century European philosophy to treat the idea of a "mind-independent world" as something ineffable or mysterious, and to treat experiences or perspectives as fundamental.

(Edit: G.E. Moore seems to think that everyone in the 19th century was making an error along these lines, but I now suspect Kant himself wasn't making this mistake; I think his main error was trying too hard to defeat skepticism.

I also don't think Berkeley's writing would have been sufficient to confuse Europe on its own; it's too lucid and well-articulated. The transition to Kantian and Hegelian versions of these arguments is important because they were much more elaborate and poorly expressed, requiring a lot of intellectual effort in order to spot the inconsistencies.)

My unscholarly surface impression of the turn of the 20th century is that these memes ("the territory is fundamentally mysterious" and "maps are sort of magical and cosmically important") allowed a lot of mysticism and weird metaphysics to creep into intellectual life, but that ideas like those are actually hard to justify in dry academic prose, such that the more memetically fit descendants of idealism in the 20th century ended up being quietist ("let's just run experiments and not talk about all this weird 'world' stuff") or instrumentalist / phenomenalist / skeptic / relativist ("you can't know 'world' stuff, so let's retreat to just discussing impressions; and maybe you can't even know those, so really what's left is power struggles").

Today, the pendulum has long since swung back again in most areas of intellectual life, perhaps because we've more solidly settled around our new central authority (science) and the threats to centralized epistemic authority (religious and philosophical controversy) are more distant memories. Metaphysics and weird arguments are fashionable again in analytic philosophy; behaviorism is long-dead in psychology; and quietism, non-realism, and non-naturalism at least no longer dominate the discussion in QM, though a lot of Copenhagen slogans remain popular.

The above is a very simple picture featuring uneven scholarship, and history tends to be messier than all that. (Ideas get independently rediscovered, movements go one step forward only to retreat two steps back, etc.) Also, I'm not claiming that everyone endorsed the master argument as stated, just that the master argument happened to shift intellectual fashions in this direction in a durable way.