Source: 6 minutes 4 seconds juncture, Lecture 12-4 (transcription), ... How to Reason and Argue,
by Prof Ram Neta PhD (U Pittsbugh; in Philosophy)
But not every attempt at reductio ad absurdum works. Consider this one.
[1.] Premise: Some things exist even though no one is thinking of them.
[2.] Conclusion: Therefore, reality exceeds the reach of the mind.
[ie:] There's more to reality than there is in the mind.Now suppose someone challenges [1] [...] as follows. They say, look,
you're saying that some things exist even though no one is thinking of them,
but as you're saying that, presumably you're not just mouthing the words.
You're really thinking it. You're thinking that some things exist even though no one is thinking of them. But if you're thinking that proposition, then you are thinking of those things.
So whatever those things are that illegibly exist, even when no one is thinking of them, well you're thinking of them right now. And so the proposition
[...] that some things exist even when no one is thinking of them [...]
is not true; because you're thinking of those very things right now
(Those very things that exist even though allegedly no one is thinking of them.) [...]
What's wrong with this attempt at a reductio ad absurdum of the premise of this argument?
Please clarify and explain what is wrong?