Mr. Browning (alias Mandeville) replies by the parable of a garden in which beneficent and noxious plants grow side by side.  “You must either,” he declares, “admit—­which you do not—­that both good and evil were chance sown, or refer their joint presence to some necessary or pre-ordained connection between them.  In the latter case you may use your judgment in pruning away the too great exuberance of the noxious plant, but if you destroy it once for all, you have frustrated the intentions of him who placed it there.”

Carlyle reminds his opponent of that other parable, according to which it was an enemy who surreptitiously sowed the tares of evil, and these grow because no one can pull them out.  Divine power and foresight are, in his opinion, incompatible with either theory, and both of these mistaken efforts on man’s part to “cram” the infinite within the limits of his own mind and understand what passes understanding.  He deprecates the folly of linking divine and human together on the strength of the short space which they may tread side by side, and the anthropomorphic spirit which subjects the one to the other by presenting the illimitable in human form.

Mr. Browning defends his position by an illustration of the use (as also abuse) of symbols spiritual and material; Carlyle retorts somewhat impatiently that in thinking of God we have no need of symbolism; we know Him as Immensity, Eternity, and other abstract qualities, and to fancy Him under human attributes is superfluous; and Mr. Browning dismisses this theology, with the intellectual curiosities and intellectual discontents which he knows in the present case to have accompanied it, in a modification of the Promethean myth—­such a one as the more “human” Euripides might have imagined.  “When the sun’s light first broke upon the earth, and everywhere in and on this there was life, man was the only creature which did not rejoice:  for he said, I alone am incomplete in my completeness; I am subject to a power which I alone have the intellect to recognize, hence the desire to grasp.  I do not aspire to penetrate the hidden essence, the underlying mystery of the sun’s force; but I crave possession of one beam of its light wherewith to render palpable to myself its unseen action in the universe.  And Prometheus then revealed to him the ‘artifice’ of the burning-glass, through which henceforward he might enslave the sun’s rays to his service while disrobing them of the essential brilliancy which no human sight could endure.”

In the material uses of the burning-glass we have a parallel for the value of an intellectual or religious symbol.  This too is a gathering point for impressions otherwise too diffuse; or, inversely conceived, a sign guiding the mental vision through spaces which would otherwise be blank.  Its reduced or microcosmic presentment of facts too large for man’s mental grasp suggests also an answer to those who bemoan the limitations of human knowledge.  Characteristic remarks on this subject occur at the beginning of the poem.