Convention

Blake was in anything unconventional.  Here is what Malcom Macdonald had meant by that:

The beginning of The Sanity of William Blake"

All criticism is based upon some 
standard of convention. Yet, in 
spite of the fact that our edu- 
cation necessarily favours such 
standard, our instincts are often finely re- 
bellious in their repudiation of convention. 
And we secretly honour all who outdare 
custom, though we openly fear and perhaps 
deride them. The weakness of convention 
as a standard of criticism lies in this, that 
we are able to estimate a given work only 
so long as it falls within our educational 
experience ; whereas if it does not, there 
remains no system that will give it justice. 
How can one judge, say, of ethics in Mars, 
when he is entirely ignorant of its condi- 
tions ? or of habits in Mile End if he do 
not share its quite reasonable dislike of his 
own culture ? or of manners in May Fair 
when he can but envy, not emulate, its 
comfortable morality ? We publicly pity 
and even pretend to despise all who are not 
of the fold ; yet in our hearts we often 
admire them. It is indeed curious. Though 
we know our conventions are but dummies 
of formalism, we cringe like very Pharisees 
before them and hug it to our hearts that 
we are as other men. Nevertheless, though 
the Gentiles defy our Gods, we grant them a 
right to live as long as they do not question 
our respectability or marry our daughters. 
Are they not picturesque, these outlaws, and 
do they not add to the gaiety of life ? Be 
they inspired poet or filthy fakir, sour- 
hearted Diogenes or pearly-toothed nautch 
girl, we gaze at them from afar and marvel 
even if we profit nothing by their example. 
In brief, those who are caged have mighty 
respect for those who fly ; if only, alas ! 
until some one shall bring the birds to earth 
with broken wing. The genius, the prophet, 
the poet, is necessarily in his work and 
mode of life outside the law that binds the 
masses into correct behaviour. Therefore 
he is beyond understanding, though the 
ignorant people may follow him from afar. 
He is beyond understanding, because few 
have virtue enough to gauge the uncon-  
ventional virtues. The schools judge only 
by their standards of examination, and cast 
out a poet as unfit. The professions 
measure by the success of their sleekest 
members ; and, as it is a law of nature that 
the eccentric shall not survive, they starve 
him. The academies of Art can judge of 
nothing that is not so firmly and viciously 
correct that all fear of its kindling the 
imagination vanishes.