Response to Postmodern Theory (Plato's Cave)

I'll summarise our core difference in this analogy: both of us believe in an objective reality, a singular unified territory out there. But I also believe that we can make maps of such a territory in an objective way, such that the maps, always ridden with errors, can nevertheless be improved upon successively and indefinitely, getting us ever closer to the territory. You, on the other hand, think the tools of map-making are themselves something we've constructed, something which co-evolves with our maps. So you can't quite say that we can meaningfully progress towards the territory, all we can achieve is consensus, a transient stability of alignment.

Maybe this doesn't perfectly summarise your view, but I think it's good enough to get us started. I will agree with you that in so many of the important problems we're concerned with, your conclusion that all we can achieve is only a transient stability, is absolutely true. And my guess is that where this way of thinking goes wrong (from my point of view) is conflating the practical realities of such cases with the possibility of objectively improving maps of certain constrained territories.

A good example of the former: what is a mental illness? Perhaps naively it might sound like an objective question with an objective answer, and so it falls within science, specifically psychiatry. But it is really only a question of categorisation; it's merely a phrase to draw boundaries around two types of people, the mentally ill and the mentally well, so that we can partition the world in these two ways and treat people differently accordingly. Is it an objective boundary? No. Homosexuality was once considered to be a mental illness, to be a disorder which must be cured by injecting medicines into their bloodstreams. Countless lives were pointlessly destroyed this way.

What is considered mentally ill, like so many other questions which look like they have objective answers, are merely a product of consensus: is murder wrong? What is a woman? Is transgenderism a mental disorder? And for all such questions, the best we can hope for is a consensus, and even then, it's not saying much; it's not even attempting to track a territory, it's attempting to box people and ideas in a way that makes it easier to deal with.

Now where I diverge from this point of view is when we say all knowledge is of this kind. One just has to look around, notice all the technological marvels surrounding us, notice how starkly different it looks from the caves of prehistoric humans, to immediately dispel any illusion that objective progress in knowledge is not possible.

I want to differentiate between two ways of looking at truth. Early in your description you say:

"truth can no longer mean mere correspondence between propositions and reality ... Instead, truth becomes a kind of alignment, which is a temporary stabilization within the network of language, perception, history, and technology, and so on that allows something to appear as meaningful."

These are two different things, and when you define truth to mean something else, its earlier meaning doesn't disappear. Truth itself doesn't morph into anything else; it's only that there's a new entity which is now being called the truth. And I agree that this new thing which can be conceptualised as a shared idea which people agree upon, is merely a result of consensus. The two notions of truth apply in two different spheres, although in both spheres there are things which are considered the truth at any given time — that is true both in descriptions of reality as well as categorisations of reality — but in only one sphere is there an objective truth which can be approximated. This is the crucial distinction and the reason we're disagreeing so much.

But why am I so confident that Reason is the sort of thing which is objective, which stands outside and gets us closer to reality, even when it's constructed by us? Only because any attempt to disqualify reason has to use reasoning to do it, and is hence self-defeating.

To be more precise, what I'm calling reason is just the application of logic over knowledge of a system. Suppose I say I know that all men are mortal and that I know Socrates is a man. With this knowledge, I can use the principles of logic (which is isomorphic to set theory, in this case) to conclude that Socrates is mortal; you need only draw the Venn diagram to find the result self-evident. Or let's say I have a complicated computer program which takes a number as input and though it does complex operations inside, suppose you realise that it outputs 0 if the input number is odd and 1 if it's even; now when asked what it will output when the input is 53, you reason that it is 0. All to show that reason is nothing fancier than logic itself applied to a domain.

Map-making or knowledge-creation, however, isn't merely a result of reasoning. You can't start from some knowledge of the world and reason your way up to the General Theory of Relativity. You can't even start from observations and generalise to get it. You have to conjecture a theory, which is an act of human creativity brought out by intuitions and hunches and malformed thoughts, on which reason is then applied; the premises of these conjectures are criticised by showing logical contradictions, inconsistencies with existing truths, etc. This is how we make objective progress, and it all starts with a problem.

At any given time, we already have theories. And if we don't yet have good scientific theories, we would have myths. These theories or myths will have errors, and we creatively conjecture a new theory, which is then criticised to make sure it's not false, and this new theory might itself contain different errors but it would have solved our previous errors and upgraded our understanding of reality, and that's how we make objective progress in science. This fact need not be taken on faith; we have indeed made such progress, which is why we're able to communicate through a screen while sitting halfway across the globe from each other. That we could make scientific progress of this sort was never under debate; the only question was how we managed to do it, and that's where Popper's insight of how knowledge grows is revolutionary.

I am not saying that we would always make progress, that when we update our theories it wouldn't get worse; it very well can. What's considered to be true is still a result of consensus. The thing which gets communicated to the public as established science is brought out of consensus. Whether or not that gets closer to reality or farther away from reality is dependent on many other factors, of course, including the norms of institutions, the cultural values, the scientific values, and it co-evolves with us, but all of that is not to be confused with the possibility that we can make progress in an objective way.