I trust I have not wasted breath:
I think we are not wholly brain,
Magnetic mockeries; not in vain,
Like Paul with beasts, I fought with Death;


Not only cunning casts in clay:
Let Science prove we are, and then
What matters Science unto men,
At least to me? I would not stay.


Let him, the wiser man who springs
Hereafter, up from childhood shape
His action like the greater ape,
But I was born to other things.

Tennyson brings to bear what he knew of the science of the human brain, it’s electric/ magnetic connections. He knows that brain drives certain aspects of human development, but he relegates it here to the limitations of a “greater ape.” It is remarkable that with his view of the importance of feelings he thinks that animals are automata.

He rejects any identification of human intelligence with mere brain-power. He knows he is other.