'They do not constitute a group or school.
Usually, though not always, they have worked in isolation
both from each other and from the orthodox art production around them.'
'If it is possible at all to point to any quality which the best work has in common
with that of sophisticated artists, it is a power of pictorial construction (lacking almost always
in the work of children and psychotics) and a power to invest the depiction of the commonplace
and familiar with a poetic freshness which imparts to it the force of visual revelation.'