The reason I suppose to be this. In art the difficulty appears to lie more in the execution than in the invention, while with poetry the contrary is the case. There the execution seems easy in comparison with the invention. Had Virgil copied the twining of the serpents about Laocoon and his sons from the marble, then his description would lose its chief merit; for what we consider the more difficult part had been done for him. The first conception of this grouping in the imagination is a far greater achievement than the expression of it in words. But if the sculptor have borrowed the grouping from the poet, we still consider him deserving of great praise, although he have not the merit of the first conception. For to give expression in marble is incalculably more difficult than to give it in words. We weigh invention and execution in opposite scales, and are inclined to require from the master as much less of one as he has given us more of the other. There are even cases where the artist deserves more credit for copying Nature through the medium of the poet’s imitation than directly from herself. The painter who makes a beautiful landscape from the description of a Thomson, does more than one who takes his picture at first hand from nature. The latter sees his model before him; the former must, by an effort of imagination, think he sees it. One makes a beautiful picture from vivid, sensible impressions, the other from the feeble, uncertain representations of arbitrary signs. From this natural readiness to excuse the artist from the merit of invention, has arisen on his part an equally natural indifference to it. Perceiving that invention could never be his strong point, but that his fame must rest chiefly on execution, he ceased to care whether his theme were new or old, whether it had been used once or a hundred times, belonged to himself or another. He kept within the narrow range of a few subjects, grown familiar to himself and the public, and directed all his invention to the introducing of some change in the treatment, some new combination of the old objects. That is actually the meaning attached to the word “invention” in the old text-books on painting. For although they divide it into the artistic and the poetic, yet even the poetic does not extend to the originating of a subject, but solely to the arrangement or expression.[82] It is invention, not of the whole, but of the individual parts and their connection with one another; invention of that inferior kind which Horace recommended to his tragic poet: Tuque Rectius Iliacum carmen deducis in actus, Quam si proferres ignota indictaque primus.[83] Recommended, I say, but not commanded. He recommended it as easier for him, more convenient, more advantageous: he did not command it as intrinsically nobler and better.