In the 20th century, everyone knew that the mind was more than just the brain, since simple introspection could determine the existence of a consciousness inexplicable in simple material terms.
No, they didn’t. Superficial research indicates that serious materialism goes back to at least the Enlightenment in the 18th century. And the 20th century? That’s not even plausible.
I don’t know how many people here would agree with the following, but my position on it is extreme relative to the mainstream, so I think it deserves a mention:
As a matter of individual rights as well as for a well working society, all information should be absolutely free; there should be no laws on the collection, distribution or use of information.
Copyright, Patent and Trademark law are forms of censorship and should be completely abolished. The same applies to laws on libel, slander and exchange of child pornography.
Information privacy is massively overrated; the right to remember, use and distribute valuable information available to a specific entity should always override the right of other entites not to be embarassed or disadvantaged by these acts.
People and companies exposing buggy software to untrusted parties deserve to have it exploited to their disadvantage. Maliciously attacking software systems by submitting data crafted to trigger security-critical bugs should not be illegal in any way.
Limits: The last paragraph assumes that there are no langford basilisks; if such things do in fact exist, preventing basilisk deaths may justify censorship—based on the purely practical observation that fixing the human mind would likely not be possible shortly after discovery.
All of the stated policy opinions apply to societies composed of roughly human-intelligent people only; they break down in the presence of sufficiently intelligent entities.
In addition, if it was possible to significantly ameliorate existential risks by censorsing certain information, that would justify doing so—but I can’t come up with a likely case for that happening in practice.