158 THEARCHITECTURE
OF HUMANISM
themainsubstantial,andof
whichtheseriousinterest
ismanifest,can
'
carry
'
acertain
measureofevident
illusionand,needlessto
say,anindefiniteamountof
illusion whichescapesalldetection
save thatof
the
plumb-lineand measure. An entire facadeof false
windows
maybetheatrical. Asingle suchwindow,
especially where
its practical necessity is for
any
reasonobvious,lowersinnosenseourconfidencein
the design. Between these extremesthe justifiable
limitsoflicencearediscoverableonly—
^andweredis-
covered
—
^byexperiment.
We:have dweltmerely on afew conspicuousex-
amplesofthemoraljudgmentinarchitecture,select-
ing fordefencetheworst excessesofthe most 'im-
moral
'
ofthestyles. Themainprincipleinallthese
matters
is clear: the aesthetic purposeofthe work
determinesthemeanstobeemployed. Thatpurpose
mightconceivably give
aclue tothe natureof
the
artist—tohisfundamentaltendenciesofchoice. But
wemustunderstandit
rightly. Themoral
judgment,
deceived by a false analogy with conduct, tends
to intervene before the aesthetic
purpose
has been
impartiallydiscerned.
Anartistmayfailinwhathe
hassetbeforehim,hisfailuremay
beamoral
one,a
recognisable negligence,
but it is manifested,
none
the
less,inanaesthetic
failure,andisonlytobe
dis-
coveredforwhatitisbya
knowledgeofthe
aesthetic
purpose. It follows