Wizard/Muggle "Radar"

[justcarol67]

No: HPFGUIDX 109507

> > Carol <snipped>
> > Draco seems certain in GoF that the DEs who are tormenting the 
> > Muggle Roberts family will instantly recognize Hermione as a 
> > Muggleborn and subject her to the same treatment, so I think some 
> > such "radar" does exist, only maybe in the opposite way to what 
> > Kristen is suggesting.
> 
Nora:
> It's an interesting subject; but I always read Draco as basically 
> being rather hateful and snotty here, and blustering in an attempt 
> to be 1) intimidating 2) appear more in the know about what is going 
> on.  Given that the blood distinctions don't have any actual 
> existence in reality in the Potterverse (I think this is part of how 
> the world works, and would love to talk this point out a little
more--but reading her current comments on blood, this seems pretty 
> canonical), this makes a lil' more sense.
> 
Carol:
> <snipped>> 
> > It also seems that Tom Riddle could identify the Muggleborns at
> > Hogwarts even in Diary!Tom form, and evidently the basilisk could,
> > too. And yet it seems likely that this radar doesn't extend to
> > Half-bloods, since Tom himself probably passed as a pureblood at
> > Hogwarts, making sure that his Slytherin friends knew nothing of 
> > the Muggle orphanage he returned to every summer.
> 
Nora:
> Tom Riddle was handsome and it seems, pretty well liked and
popular--there's that ...odd closeness to Hagrid, too. I wouldn't be 
> surprised that he had the information on the social background of 
> his fellow students, as it doesn't seem to be kept terribly secret 
> in the present day.  Tom knows who is a 'Mudblood', then, and can 
> take his vengeance upon those select few.

Carol again:
That doesn't account for the Muggleborns who were petrified in CoS,
and I'm not sure that Tom was "close" to Hagrid--I think he was
patronizing him and tricking him through a use of his first name that
*seemed* friendly but was really contemptuous. Also, I'm not sure we
can brush all this aside based on JKR's rather hastily posted response
on her website (complete with the "Lily's grandparents" error).

That aside, though, because it would be too complex and time-consuming
to get into the Muggleborn aspects of the argument now (especially
since I'd have to argue that JKR's intentions and assumptions are not
necessarily substantiated by the canonical evidence of the books), I
want to return to the original question of whether Arthur or any other
pureblood could detect a wizard posing as a Muggle or vice versa. I
don't think we've yet seen any witch or wizard misidentify a
Muggle--McGonagall, for example, doesn't hesitate to label Petunia and
baby Dudley as "not us"--Muggles of the worst kind, in her view. And
of course, no one has any difficulty identifying the Muggles at the
WQC--they're the ones assigning the camping spaces. (Nobody really
seems to know how to dress as a Muggle, though--not even Arthur, which
is more than a bit odd, IMO.)

But--and I'm finally getting to the point I want to make--whether or
not a wizard can recognize a Muggle on sight or through some sort of
wizard "radar," it clearly *is* possible to put a Muggle-detecting
charm on an object and recognize them in that way. Hogwarts and the
QWC have Muggle-deterring charms, and the Rumours section of JKR's
website advertises Muggle-deterring gates that emit alarms (cackles,
screeches, etc.) at the touch of a nonmagical finger. So in theory, at
least, if Arthur or an auror--or a DE--wanted to determine (for
whatever reason) whether a person was a Muggle or a witch/wizard, he
could carry around a small Muggle detector, a charmed device that
detected the presence or absence of magic in the person it was aimed
at. Or he could just place a wand in the person's hand and ask him to
swish it in the air. If it emits sparks, he's a wizard. If not, he's a
Muggle--or a Squib.

Which raises the question: Would a Muggle-deterring gate alarm go off
if a Squib touched it? I don't think it would, since Filch is not
affected by the anti-Muggle charms around Hogwarts. (Or maybe he can't
leave the grounds because he wouldn't be able to find them again
without the help of a witch or wizard?)

Admittedly, none of this relates to the detection of Muggleborns, who
obviously *are* magical regardless of their "blood," so maybe Draco
really was full of hot air and Tom had some means of identifying them
other than his own instinctive recognition of "Mudbloods." But Muggles
are another matter. Clearly *they* can be both detected and deterred,
if not by a built-in wizard radar, then through charmed objects that
detect the presence or absence of magical ability, even at a distance,
like the MoM radar or the Hogwarts quill.

Carol