Why do you think Cartesian dualism is still taken seriously as a valid approach in the academia despite the criticism?
Sorry for this long post, my major is in theoretical linguistics, but I've also taken classes in philosophy and physics, and this issue is relevant to all branches of science and humanities. I'll use Noam Chomsky as an example, but this can be applied to basically any dualist, such David Chalmers, who reacts to criticism by moving the goalposts and rejects materialism, because they want to protect the perceived uniqueness of the human ego.
Why do you think Chomsky's obviously unscientific hypotheses (not "theories", which many ppl call their ideas to make them sound more plausible) are treated as an almost indispensable part of linguistic education (i.e. not as part of the history of the evolution of linguistics as a field, but as a still active area of study relevant even today)? Yes, there are some critics, but his ideas are still taught as if they were true or at least the most likely framework. While in reality, most of his points are either completely unfalsifiable Cartesian dualist philosophy or - when falsified and shown to be incorrect - he moves the goalposts and changes his original definitions, essentially creating a God of the gaps instead of a scientific theory.
His internalist approach treats language as a biological faculty with an infinite potential, but it is, by definition, also a set of constraints. He says that even the mildest version of linguistic relativism is wrong, because we're all born with the same potential for understanding and learning, so he would reject the concept of a child being able to learn a truly alien language that e.g. marks grammatical cases with circumfixes, as he argues it'd be physically impossible, because the brain doesn't have the neural wiring to make sense of such a morphology (in other words, alien languages wouldn't even be classified as languages in the humans sense, because the aliens would have differently wired brains). He argues that without these innate limitations (UG), a baby wouldn't be able to learn any language at all. If the brain were a blank slate open to every theoretical possibility, it'd be overwhelmed by the infinite data. By having a narrow path, the baby can learn a complex language in just three years. So he rejects relativism, because he thinks our brains have the same biological limitations, and alien languages are "complex problem-solving tasks" that we can't even formulate in our minds. But it's just wrong: we are perfectly capable of formulating and even creating and learning theoretical concepts that aren't encountered in any modern language. He says the reason they aren't present is because the human brain doesn't have a biological space dedicated to making sense of them. But it might very well be that the reason we see a limited set of typologies, morphologies, and syntaxes is that those we don't see all died out with their speakers in Beringia or something. So it might as well be a case of our statistical bias - we literally have no data on the languages that became extinct before the invention of writing (which is why all the superfamily hypotheses are essentially unfalsifiable - it's been so many years that even if Proto-Turkic and Proto-Nivkh come from the same ultimate family, their deep genetic similarities are indistinguishable from random chance). Also, there are literally just individual single languages that have a feature that every other language lacks. Why would that 1 instance of a feature be different from those potential features with 0 real-language instances? They might as well be at least theoretically realisable just like those singular features. And with progress in neuroscience, we have empirical proof that the brain is incredibly plastic and actually has the physical potential to learn statistically implausible things (e.g. we can all be temporarily turned into savants by having specific regions in our brains electrostimulated). So the fact that we can think of and define our limitations may actually prove they aren't limitations at all. He has no empirical proof that there is a separate area in the brain responsible solely for language. What if the fact we can think of our limitations points to the possibility that the entire brain is ALWAYS involved in everything we do, be it language, maths, puzzles, cooking, whatever? Just because certain areas might light up brighter during certain activities doesn't mean that those other areas are uninvolved (this is actually what modern connectionist neuroscience suggests - that language is a whole-brain event). His counter-argument is the supposed poverty of the stimulus (i.e. babies hear so little "perfect language" that they couldn't possibly learn it without an innate head start). But a baby isn't just a language learner - it's a statistical pattern-learning supercomputer. The brain doesn't need a language module if it's already designed to find patterns in everything. So if the brain as a whole has the potential for evolution, then Chomsky's "limitations" aren't biological dead ends but evolutionary snapshots.
Chomsky rejects modern neuroscience, because it's a threat to his abstract unfalsifiable hypotheses, as neuroscience actually relies on empirical data to make assertions. Modern physics and neuroscience suggest that language is a function of the brain that has become so biologically complex that it's capable of infinite recursion (which other animals seem to have at best a limited version of) - in other words, language is an emergent property of the brain as a complex, purely biological system. Whereas Chomsky WANTS language to be a mysterious result of a single genetic mutation that somehow created a literal physical area inside the brain responsible solely for language, that is functionally separated from the other areas. But language is rather just another self-contained logical system of patterns, just like maths is. Why would the brain have a separate area just for this one specific system if it can learn many other systems perfectly fine too? Why would language be special? According to his logic, we should also have separate hardwired faculties for maths, chess, mahjong, etc., but this would be ridiculous. He'd probably say this comparison is wrong, because everyone learns language perfectly no matter their IQ, while not everyone can learn to play chess. But as I said, we're actually physically capable of becoming savants, it's just that this potential is not equally realised, because it's a later invention that isn't evolutionarily necessary for survival, unlike language, which is an advanced form of social grooming.
He fears that if we admit language is just general learning, we lose what makes humans unique. He wants language to be a biological "leap" that happened in our evolution, separate from the slow development of general intelligence. He pretends to be a materialist atheist who rejects unscientific claims, and that he separates his linguistic hypotheses from his political views, but his ideas are actually no different from theological explanations. He wants us to be unique, so he implicitly claims that language is a ghost in the machine from some neo-Platonic realm of pure logic that only humans are capable of unlocking and actualising within the physical reality of the Universe by developing a specific genetic mutation that creates a physical channel for the "spirit of language" to inhabit (he later started calling this supposed logical operator of recursion "Merge").
I think Chomsky basically doesn't want to admit that he wants there to be a metaphysical realm inhabited by souls that only humans have while animals are mindless automata (he stole this concept of Cartesian dualism from René Descartes, btw.). If language is emergent and contingent (which is what modern empirical science suggests), then anything the brain can process can be language - i.e. if that alien language I mentioned is functionally the same as human languages, then it is a language too, just one that hasn't been evolutionarily realised yet here on Earth. But if language is a Platonic axiom (Chomsky's view), then anything that doesn't fit his specific "Merge" math is not-language, even if it works perfectly. He clings to his ghost because he wants to protect the "dignity of man". He thinks that if we are just better statistical animals, then our lives, poetry, and thoughts have no special meaning. So he's saying that language both evolved from a single biological mutation (which is physically observable, so should be scientific if ever found, which it hasn't) and that this mutation is what somehow unlocked the non-physical logical realm of language that existed before the mutation. By claiming that the logical realm of language is hard-wired and untouchable by experience, he's defending a pre-deterministic worldview. Just as a religious person believes their fate or nature is decided at birth, Chomsky believes our linguistic nature is decided by our species' blueprint. To him, the "statistical God" (the learning brain) is a threat because it implies we are free to become anything based on our environment. So he finds the idea of limitless learning as terrifying as a priest finds "moral relativism". But that's not empirical science, that's metaphysical idealism.
What he doesn't understand is that humans can still be unique even if language is just a statistical function of an advanced biological brain. We're unique simply because our brain is the most advanced among all living organisms. If the Universe is indeed fundamentally logical/mathematical, then the only thing that makes objects unique are the differences between their specific sets of data points. What makes the human brain unique is that its data points have the densest values out of all animals, not that there exists some abstract "spirit of language" that inhabits the human brain while ignoring all other brains. That's just some weird fantasy novel.
So it's not that animals and humans have different essences (i.e. Chomsky says the language faculty is a categorically separate thing-in-itself that requires its users to be human), it's just that humans are animals with more of the shared animal essence. Animals are capable of matching patterns (A -> B), while humans are also capable of matching patterns of patterns (A -> [B -> C]). Because our "statistical God" brain is so big, we can perceive patterns that are so complex we call them "grammar".
Chomsky's hypotheses are an unfalsifiable set of religious dogmas that result from his humanistic approach, which leads to the paradox of special pleading. If we follow his logic, we might as well claim that all genetic mutations are just switches that unlock self-contained abstract universes every time they occur, like the mutations that gave animals their legs were actually switches that unlocked the abstract realm of "legness" or the mutation that gave us blue eyes unlocked the realm of "blue-eyeness". But he doesn't do that. He treats legs as a physical adaptation to the environment, while treating language as a mystical encounter with an abstract realm. This inconsistency shows that he isn't following a unified theory of biology but making an exception for the human mind. He avoids this because he wants to be a scientist for everything except the human mind. He's a materialist for the body but a Platonist for the brain.
He can't accept that a finite, statistical brain can produce infinite variety. But he doesn't understand that the seeming infiniteness of recursion is not truly infinite. If he was a materialist, he would accept that the Universe is a set of logical distinctions, and the Universe consists of a finite set of physical laws too, and these finite laws give us an infinite Universe when it comes to spacetime, but the patterns eventually have to repeat an infinite amount of time. Language is the same: we have the potential to turn a finite set of patterns into an infinite amount of sentences or word strings (i.e. instances of these patterns). But these sentences don't contain an infinite amount of patterns; the patterns eventually have to repeat.
But Chomsky himself is ultimately just an old man with a very outdated understanding of science and especially physics (he justifies the unfalsifiability of his claims by saying that the Newtonian framework also involved abstract properties like gravity, so Chomsky also can introduce non-physical ghosts, but he doesn't get that modern quantum mechanics completely reverses the traditional axiomatic understanding of the world and instead suggests that logical relations and properties are the underlying reality while the physical realm is emergent from them; also, his comparison of his own ideas to Newton or Galileo is a false equivalence, because the latter simply used mathematical approximations of the underlying quantum reality for our macroscopic scale, but the quantum scale still exists, whereas his idea of a separate language faculty has no basis in physical reality at all, it's just wishful thinking). What is more concerning is that there are still new generations of Cartesian dualists in linguistics, philosophy, and, unfortunately, even physics (cf. all the superstring or multiverse theories that just add new unfalsifiable conditions rather than working with the ones we already have). Sabine Hossenfelder, as clickbaity as some of her stuff is, was right about the sad state of the academia. Do you think the academia still clings to these unscientific ideas, because they generate money? Or rather because so many academics act llike cultists who worship the most famous figures, which creates intellectual inertia? Or maybe because students of philosophy, social sciences, some branches of linguistics, etc., deep down feel intellectually inferior to hard sciences like maths and physics, and want to appear more serious by using convoluted language or using mathematical-ish terms in unfitting contexts?