There’s tons of evidence in-universe; even if he shouldn’t suspect by chapter 20, then by ch100 the failure has become impossible. (And I recall that knowing about canon was actually a problem for a lot of people: “surely it can’t be that obvious? Eliezer would never take such an obvious tack!”)
I personally feel unsure what the Defense Professor wants, if he’s the Dark Lord Tom. My tentative guess is, nsgre gur Qrzragbe snvyrq gb shysvyy gur cebcurpl, ur qrpvqrq gung nal fbyhgvba rkprcg qverpgyl ‘pbeehcgvat’ Uneel gb funer uvf tbnyf jbhyq whfg oevat n arj fcryy vagb rkvfgrapr. Guvf zvtug rkcynva jul ur qbrfa’g whfg qebc n ebpx ba Uneel be fgnaq nfvqr sbe gur pragnhe, bapr ur fgnegf gb ernyyl srne arj fcryyf.
Guvf ulcbgurfvf vapernfrf gur punapr gung Gbz unf tvira Uneel’f arj cneragf n gvzr-qrynlrq vyyarff (gung bayl ur pna erzbir) be bgurejvfr chg gurz va Obk N nf n onpxhc. Fb V’q orggre or evtug nobhg gur Qrnguyl Unyybjf nf jryy.
Well, part of it is that Quirrel is Voldemort in canon, which is significant evidence that Harry doesn’t have.
There’s tons of evidence in-universe; even if he shouldn’t suspect by chapter 20, then by ch100 the failure has become impossible. (And I recall that knowing about canon was actually a problem for a lot of people: “surely it can’t be that obvious? Eliezer would never take such an obvious tack!”)
I personally feel unsure what the Defense Professor wants, if he’s the Dark Lord Tom. My tentative guess is, nsgre gur Qrzragbe snvyrq gb shysvyy gur cebcurpl, ur qrpvqrq gung nal fbyhgvba rkprcg qverpgyl ‘pbeehcgvat’ Uneel gb funer uvf tbnyf jbhyq whfg oevat n arj fcryy vagb rkvfgrapr. Guvf zvtug rkcynva jul ur qbrfa’g whfg qebc n ebpx ba Uneel be fgnaq nfvqr sbe gur pragnhe, bapr ur fgnegf gb ernyyl srne arj fcryyf.
Guvf ulcbgurfvf vapernfrf gur punapr gung Gbz unf tvira Uneel’f arj cneragf n gvzr-qrynlrq vyyarff (gung bayl ur pna erzbir) be bgurejvfr chg gurz va Obk N nf n onpxhc. Fb V’q orggre or evtug nobhg gur Qrnguyl Unyybjf nf jryy.