Neither my brain nor your brain, nor anyone else’s (or anything’s, for that matter) needs to comprehend objective reality because there is no objective reality.

I tell you this not as a student of Philosophy but as a professional (neuro)psychologist with decades of experience: not simply anything but everything you, I or anyone else experiences is a construct … quite literally a figment of our imagination. There is even a 500 millisecond delay between an external stimulus and our conscious perception of it, that our brain subconsciously factors in to our appreciation of when events take place in time — a delay we never become aware of ourselves because our brain doesn’t tell us about it but, instead, fakes to us when we perceive things to happen.

Whatever might be out there in the real world, there is not only no way for us to ever know to what extent (if at all) our neurocognitive model might correlate with it but our model can in no way, shape or form be claimed to be related to it except by sheer coincidence. At most … at the very most … the neural modelling that takes place could be said to be the result of the external universe acting as a stimulus to which our brains respond by constructing a model. That, however, is where the relationship ends as far as can be scientifically determined … all else is speculation and always will be. Because the brain feeds back into itself and, once set in motion, needs no external input in order to do so — the brain is not like a Von Neumann architecture computer … not even remotely.

I don’t. for a second, doubt the existence of an external, physical universe myself … but there is not an external reality to which we may refer in any way that is meaningful. Ingest the right substances … whether the result of recreational substance abuse or accidentally (like with food poisoning) is immaterial … and you will experience an entirely different reality to the one you would otherwise experience — and it will be no less real for that (because your experience of it will be real in and of itself). The Universe might be real, but Reality is not a thing … it’s an ongoing experience that arises from the biochemical structure and activity of the brain.

Supporting social programmes, UBI or whatever is laudable … I think we’d both agree on that at least … but that says nothing about the fundamental tenets of your thinking, which will be the result of the culture in which you are steeped.

If we are lucky enough to live in different ones for appreciable periods of time, at stages in our lives when we are sufficiently mature (not simply as children) then it can be easier to recognise the limitations in our thinking that stem from this, because we have frames of reference against which we can compare each of them. But even then, unless the cultural differences are radical … such as requiring multilingualism … we are unlikely to be terribly aware of our own thinking as a product of a society/culture — the differences between US and UK thought are not as great as between US and Japanese thinking, for instance … and whilst the difference in thought between various European cultures might be significant, that seeming significance is put into perspective when any of it is compared with that of an African or Middle Eastern culture.

So, really, whilst you might be convinced your thinking is (radically) left of centre in the US, to us here in Europe, your most radically left-wing thinkers are far to the right — trust me, there is no left wing in the US, let alone a radical one … not as Europeans would recognise it. From here, the degree of Randian influence on your thinking is as clear as is that of Isaac Newton on modern Western thinking in general. You might be opposed to it, but it is still there … your a priori cultural assumptions still influenced by it in a way they are not even the UK (which loves to ape the US to no small degree, especially since Margaret Thatcher), let alone any of the other, more socioeconomically liberal, states in Western Europe.

The fact that you can, seemingly in all seriousness, declare that a society (or, indeed, any group) may not do as it chooses irrespective of what anyone else might think, only as you stipulate, renders everything else you might have to say on the matter not merely intellectually destitute but morally bankrupt right from the outset … but to then go on and claim that “Modern anarchism is a far-left anti-liberal concept” simply confirms that … whether you recognise it or whether the cognitive dissonance is simply too great for you to see beyond … your a priori axia are so steeped in post-Randian US Capitalist ideology that you would no more recognise that you need to put the atlas down and step away from the fountainhead than a fish would recognise that it is surrounded by water.

As for the ‘slippery slope towards postmodernism’ … look, I’ve no more time for a lot of it than you (clearly) have yourself, but you can’t expect to say things like that and expect even those who agree with you to take you seriously. Have you just completed (or are still taking) an undergrad Philosophy course/module/degree? Because phrases like just that scream ‘PPE student!’

Exacerbating the cognitive dissonance, whilst your thinking here is redolent of conservatism (the fact that you might lean left vis-à-vis US cultural norms notwithstanding) you use neoliberal terminology, such as ‘marketplace of ideas’ without seeing any disconnect between the two modes of thought. You may not be a Randroid, but your thinking is evidently as unconsciously Randian as is the thinking of any inhabitant of the former USSR Lenninist — as was … ironically, but not at all surprisingly … that of Rand herself.

I’ve no doubt you mean well and I’m pretty confident we might even see eye to eye on a number of issues, but your thinking … at least as expressed here … is, sadly, horribly confused in a way that I only ever see evidenced by right-wing advocates of post-Randian US socioeconomic policy (which is, itself a philosophy of sorts, but an impoverished one) … or by those who do not even recognise that they are themselves proponents of a philosophy so far to the right that, here in Europe, the most we can do by way of politesse is smile to ourselves rather than outright laugh in their faces when they claim to be left of centre.

What you espouse in your original is libertarian, not liberal … and the problem with that is that it’s …

1. intellectually destitute — it’s just a truism that the World is anarchic … Libertarianism no more sophisticated a ‘natural’ philosophy than Rand’s own Objectivism was even a branch of Philosophy, let alone a sophisticated one.
2. so morally bankrupt as to be sociopathic: the most ardent advocate of libertarian individualism must recognise the moral rectitude of imposing my will upon them by any means I feel fit, for any reason I deem desirable — no-one wants ‘big’ government until they, or their loved ones, suffer the consequences of another’s unalienable freedom to do what they choose unfettered and unhindered by the ‘immorality’ of communalism … but then, when someone else takes the same approach, just watch them squeal with outrage rather than sanguinely accept the right of others to do unto them as they (would) do unto others (libertarians are simply those who have not yet been mugged and whose daughters have not yet been raped).

My advice would be to perform a root-and-branch analysis of the baggage dumped in your lap by the culture in which you have been socialised. Get rid of anything that doesn’t stand up to scrutiny, however painful that process may be — you will, inevitably, have to let go of some dearly held views, so it will be … very.

Equally, put down the PPE texts (figuratively speaking) and study some Psychology (even Sociology at a pinch). Because Sartre was right: what matters is how we act — inevitably so it’s the only logical step after the realisation that both Descartes and neuroscience/neuropsychology dictate that you will never know that it isn’t all real. You wanna understand it … study Psychology (maybe a bit of Sociology). You wanna make a difference … become a politician/lawyer/doctor/whatever and make concrete changes to people’s lives. But sitting around contemplating how many ̶a̶n̶g̶e̶l̶s̶ of the underprivileged can dance ̶o̶n̶ ̶t̶h̶e̶ ̶h̶e̶a̶d̶ ̶o̶f̶ ̶a̶ ̶p̶i̶n̶ in a squalid, taxpayer-funded bedsit owned by a sociopathic, non-dom, fat-cat rentier landlord is for the intellectually and morally disenfranchised ¹ — a ‘marketplace of ideas’ might sound good when espoused on an alt-right / libertarian bbs … it won’t cut any ice with a social worker dealing with an incel’s fifteen-year-old rape-victim who didn’t appreciate the niceties of the ‘debate’.

(N.B. Psychology, Psychoanalysis and Psychiatry are three very different things … do not mistake them for each other — Freud and Jung are bunk and there’s more to the science of understanding the human condition than learning when to stage a pharmacological intervention).

When you’re done, you might then appreciate just what was wrong with advocating free speech irrespective of the sensibilities of others: I might find something abstractly unproblematic, but someone else might be traumatised by it and it would be morally reprehensible of me to insist on my right to discuss it irrespective of that. Abstract ideas do not exist … everything exists in a context. And that context consists, above all, of other people whose lives may … will … be impacted by your free-for-all, anything goes, ‘free market of ideas’. We have a moral obligation to them to factor that in before we blithely espouse imposing our ideology on the world we share with them — for which, as it stands, you make no allowance; your ideological attachment to your ‘free market’ overriding any thought for the needs/rights of others or of the potential validity their opinions.

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¹ Oh, look … a bitterly scornful observation based upon my unconsciously held a priori assumption that everyone has access to a (at least relatively) generous welfare system that will pay their rent / mortgage if they fall upon hard times and that the image will resonate with you. Moreover, it fundamentally takes for granted that you will, furthermore, be equally as disapproving of a state of affairs whereby the taxpayer funds the private, rather than public, sector (two potentially erroneous assumptions for the price of one!). See how easy it is to fall into that trap?