A simple sketch of how realism became unpopular

[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.