A small amount on intellectual disabilities (or idiocy?)

I've just started reading a fascinating and really heavy research paper.

From 'Idiot Child' to 'Mental Defective': schooling and the production
of intellectual disability in the UK 1850 -1944
by Shereen Benjamin
http://www.educatejournal.org/index.php?journal=educate&page=article&op=viewFile&path[]=48&path[]=44
<http://www.educatejournal.org/index.php?journal=educate&page=article&op=viewFile&path[]=48&path[]=44>

She (I assume it's a she)
"
One of the problems with writing about intellectual disabilities is of
knowing how
to name the phenomenon and the people about whom one is writing. This
problem has been in evidence throughout the past one hundred and fifty
years.
There can be no absolute notion of what constitutes intellectual
dis/ability, since
the means of coming to know about it is historically and socially
situated. Unlike
some physical and sensory impairments, a learning or intellectual impairment
cannot be discerned in the absence of instruments of normalisation
(Foucault,
1975). This is not to argue that intellectual impairments, whatever we
choose to
call them, do not exist. But the means of separating those who can be
categorised as intellectually disabled from the general population has been
produced through a discursive field in which the (political) imperative
to separate
out the economically unproductive from the productive has prevailed.
"

It's nice to have something expressed so well (or at least something I
agree with expressed well by someone smarter than me).