IRONCLAD PROOF THAT LUCK AFFECTS SOME CHESS GAME RESULTS

Opto is usually wrong.
So often he begins with an invalid premise or worse.
He'll try to shut down conversation with he 'already' did something.
But usually fails.
He did nothing to refute Jon's argument.

Opto is usually right

So we disagree. That's fine.
Just now he tried to argue that since good players play to increase the chance the opponent will make an error that he must be right.
It doesn't follow.
That's like saying that since 2+2 =4 then 3+3=2
Opto proved nothing. He always claims false victory too.
Nobody has to buy.

"That's like saying that since 2+2 =4 then 3+3=2
Opto proved nothing. He always claims false victory too.
Nobody has to buy."

Now you're making things up

What did I make up?
Nothing.
Nobody has to buy.
But you can.
Its especially the kids who often cave in to Opto.
But you're already better than him. .
You can admit that you're wrong. You have in the past.
Now - did Jon want these exchanges in his forum?
Maybe not.
But Opto proved nothing.
Because Jon the opening poster never claimed that good players don't play to increase the chance of the other player making an error.
Opto went after a strawman.
There. Opto's disinformation interfered with.
Efficiently.

And sure, good players play to increase the chance the opponent will err. That approach probably was always in wide use at high levels, but I have the sense it's become far more recognized and widespread in the past 15 years or so (= THE CARLSEN ERA), largely due to its association with Carlsen's playing style. (And based on the earlier discussion, inducing the opponent to err, and the opponent actually erring, is 100% SKILL not luck... so Capa's maxim about good players being lucky is irrelevant for purposes of this discussion.)

That approach also ties in with an evolution in how engines are used in opening prep. Top GMs in their prep no longer aim to find novelties that confer some objective advantage. Rather the aim is to find novelties that take opponents out of their own prep and lead to positions that are playable and more comfortable psychologically/stylistically (not necessarily objectively better) for the player who introduced the novelty than for their opponent.

Jon I agree with you that the assumptions are made.
And about imposing assumptions.
We disagree about whether the assumptions are valild or not.
I say invalid - including because they're assumptions but that's not the only reason.
Assumptions can be distinguished from logical consequences and compelling realities.

Finally, regarding the OP diagram that's being ineptly analyzed in some comments here, I'll just note that Rxd6 -- played in the game by an age-group World Champion with plenty of time on his clock, and which commenters in various Facebook chess groups sleepily posted as winning -- actually LOSES. (This was a real-life practical case of that old cliche, "Call an ambulance... but not for me!)
Detailed answers can be found in comments to the original story that's linked in my OP. That story also displays 3 positions from other games that turned luck -- resources both sides overlooked until the moment they appeared on the board. Including 2 positions from Game 1 of the recent Ding-Gukesh WCC match. (Twice in that game Ding benefited from shots he should have seen a few moves earlier than he actually saw them, when he would have been busted if they didn't exist).

Luck and skill might 'signal' mutually exclusive ...
but its a false signal.
Neither one can exclude the other in any total sense.
And not in most contexts either.
I gave an example of a single skill situation that appears to exclude luck like this ...
'a player reaches out to his Queen and sets it down checkmating his opponent's king. He calls 'checkmate' and stops the clocks too.'
Opto obsessed over the 'clocks' part and semantics of 'end of the game'.
Too late for him to take it back.
Plus he completely missed the point.
Which is that in the context of the checkmating move - luck seems to be excluded.
But in the context given - only from that move.
Not from the game or from any chess game.
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Jon do you agree that in the context of making the checkmating move - that luck seems to be excluded during that particular operation?
(calling checkmate and stopping the clocks are precautions that could be seen as part of good play at that point. Since the game is over stopping the clocks is appropriate. But rules and practices might vary from locale to locale.)

Rxd6 loses?
Well that's entertaining!
I don't doubt you. Things aren't always what they seem to be.
I could have 'cheated' and pre-checked with an engine - or spent a lot of time looking at it. 
I don't want to know why Rxd6 loses. As in not yet.
Whoever might say.
But on Rd6 losing I'll just say - nice puzzle!

I'm not interested in settling arguments between playarafar and Opto -- which seem to be a recurring bug (was gonna say "feature" but it's more a bug) on many forum topics. I didn't even see the original comment that brought up the checkmate-stops the clock hypothetical.

I will say only that disputes over whether someone completed a move before their flag fell are disputes over rules, or evidence (presence or absence of witnesses, etc.). That factor falls outside of the luck-vs-skill issue. If you want to split hairs, I guess I could add a further assumption that (to make "all games are decided by either X or Y" encompass all possibilities) both players are honest (neither is cheating in any way) and no external factors (earthquake, heart attack, inadvertent ringing phone causing forfeit) are present to affect the outcome.

@FishThatRoared
I can't do anything about Opto being in your forum.
the part about Opto and his fights with other members was a side-comment - made because I again wanted to mention verbally announcing checkmate and stopping the clocks as part of the checkmating move. (could be quite a situation if it wasn't checkmate!)
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I'm asking if whoever agrees that the checkmating move itself excludes luck from that particular point in the game.
It might be so obvious that it does - that its not necessary to get confirmation.
But the point is to contrast that with other points in any chess game.
Yes the issue of whether the move was made in time falls outside the skill-luck issue but another point is that flag down is a thing that might knock out that move.

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Making the checkmate move is perhaps not the only point at which luck might not exist because its 'pure skill' at that point. (however obvious the mating move is).
There's stalemate moves ...
'Mate in x moves' sequences - 
Moves that punish blunders however lucky it is the opponent made the mistake - the moves that then create winning advantage could be regarded as 'pure skill' which is another reason players may tend to not see 'luck' in the game.
The mind is on the position in front - what led to it is in the past no longer being concentrated on.

If one or two overly authoritarian and manipulative or passive-aggressive types choose to fight with me, I would be equally happy if they didn't.

That's right, actually. Not always, but.

But quite often.

Congratulations, you've managed to attract a MIP to your threads. Now, many people would think it a detriment.

Regarding your "position", I might have sat there for an hour and seen that the lost knight's returned but calculating the ins and outs of the resulting position would be too difficult for me to do in my head in an hour. Maybe it would take me a week, I don't know. So I wouldn't have sat there for an hour thinking about it. It would have taken two or three minutes to understand that I couldn't compute it and so I shouldn't take the knight.

I would probably play f3 without too much thought.

When I win, there is no luck in the game. When my opponent wins, they get lucky in the game. (Joke)

My background in philosphy isn't quite so academic as you might think.

If most chess players genuinely draw a clear deliniation between skill and luck, are we really going to believe them, to the extent that we allow the entire discussion to be closed down or sent along an unprofitable path due to common useage?

I might point out that footballers don't normally get into abstruse discussions on fluid mechanics when they're talking about how to make a football swerve. Why should we be dominated by what chess players may think about the interplay of luck and skill?

Pardon me for asking but

Do you have any brothers?