I think he is hinting to when I said: "For most people, most life situations which require clear thinking have nothing to do with writing."
I meant: since most life situation where we need clear thinking do not involve writing, then we are obviously well equipped to think clearly.
And if thinking clearly is not that problematic for most people, then the author can't say we can't write because thinking clearly is hard/or we can't think clearly.
You're still both missing PG's point, and getting your logic wrong for the point you are on. About the latter:
> "I meant: since most life situation where we need clear thinking do not involve writing, then we are obviously well equipped to think clearly."
That's not the QED you seem to think it is. The statement that "most life situation where we need clear thinking do not involve writing" doesn't give any reason to think that most people are good at clear thinking most of the time, nor whether people find clear thinking easier with the help of writing or if writing has no benefit to the goal of clear thinking. You're just putting two opinions you have next to each other and acting like one confirms the other.
And a friendly tip, "have I explained better what I meant before?" would come off as a lot more polite than "got it?", which to anyone who agrees with the rest of your comment could easily read as snide/patronising, while anyone who thinks you're still wrong will see it as smug and wrongly confident. (Apologies if English isn't your first language, in which case you're very good at it, and apologies if you didn't want unsolicited opinions on how your choice of language makes you seem in my view!)
edit to give an analogy: I feel your argument is like if somebody said "control of body movement is key to being a great athlete", and you replied "everyone is always controlling their body movement, clearly therefore it's not relevant to how good an athlete is".
I meant: since most life situation where we need clear thinking do not involve writing, then we are obviously well equipped to think clearly.
And if thinking clearly is not that problematic for most people, then the author can't say we can't write because thinking clearly is hard/or we can't think clearly.
Got it ?