MIND OF BLAKE

In considering the mind of Blake, I first think of what Paul said in  Romans 12:2, about how our minds should be formed and how they should function.
"Don't let the world around you squeeze you into its own
mold, but let God re-mold your minds from within, so that
you may prove in practice that the plan of God for you is
good, meets all his demands and moves towards the goal
of true maturity."

The following quote from Annotations to Reynolds, page 157; (E656) shows how Blake thought about the mind he had been given by God:

"Reynolds Thinks that Man Learns all that he Knows I say on
the Contrary That Man Brings All that he has or Can have Into the
World with him. Man is Born Like a Garden ready Planted & Sown
This World is too poor to produce one Seed"

And this quote from Milton 26.41; (E124), shows that he attributes to Spiritual Causes all that happens both internally and externally:
"Because
The Natural power continually seeks & tends to Destruction
Ending in Death: which would of itself be Eternal Death
And all are Class'd by Spiritual, & not by Natural
power.And every Natural Effect has a Spiritual Cause, and Not
A Natural: for a Natural Cause only seems, it is  Delusion
Of Ulro: & a ratio of the perishing Vegetable Memory."

Gates of Paradise: Air

The internal structure of Blake's mind was unique as is that of
each of us. His mind was molded by the genius with which he
was born; by his perceptions of the infinite; and by his
commitment to following the vision which he was given. The
reality he perceived was not the reality of Ulro but the reality
of Eternity.
Although some have doubted Blake's sanity, they must be
those who were unable to see beyond the physical world.
Blake's behavior may have seemed erratic, his interests
were obviously eccentric, and his expressions were extreme.
But he was not trapped in patterns of thought and behavior
which divided him from rationality and from functioning in the real
world, as are most schizophrenics. Blake's intellect was not
impaired, nor was his ability to present his ideas in images
which could be understood by others. Some have thought that
it was his extreme sanity which set him apart from the
conventional world.    
You may remember Arthur C Clark's, Childhood's End.
If Blake is a transitional figure, introducing humanity to the
ability to function at higher level of consciousness, he may
well be perceived as a schizophrenic or a devil by those
who fear raising consciousness.