William Blake's questions for neuroscientists

From Visions of the Daughters of Albion, a short illuminated text published in 1793:

With what sense does the tame pigeon measure the vast expanse?

With what sense does the bee form cells?

Tell me what is a thought? & of what substance is it made?

Tell me what is a joy? & in what gardens do joys grow?

And in what rivers swim the sorrows, and upon what mountains wave shadows of discontent?

Tell me where dwell the thoughts forgotten till thou call them forth

Tell me where dwell the joys of old? & where the ancient loves?

And when will they renew again & the night of oblivion past?

That I might traverse times & spaces far remote and bring

Comforts into a present sorrow and a night of pain

Where goest thou O thought? To what remote land is thy flight?

If thou returnest to the present moment of affliction

Wilt thou bring comforts on thy wings, and dews and honey and balm;

Or poison from the desert wilds, From the eyes of the envier.