Metaphysical evil, or the limitation of endowments, is inevitable in every being below the Godhead, and Pope contends that the best system must manifestly consist in an infinite series of creatures, from the greatest to the least. The notion is found in Locke and Leibnitz. There are beings, said the latter, above and below us, or there would be a void in the order of species.[820] The idea was more fully developed by Archbishop King, and is simply an extension to the universe of the terrestrial system, where a gradation of beings on a connected plan is the law. Pope carried the principle to extravagance. He contends that the omission of the smallest creature would break the chain, would throw the universe into confusion, and involve all creation in a common ruin.[821] To keep the universe from tumbling to pieces, "it is plain," according to him, that "there must be somewhere such a rank as man,"[822] and the rule holds equally of the minutest animalcule on the globe. There is a flaw in his premises. It is not apparent that the extinction of the flea would upset the universe, nor that the scale of beings must necessarily be the same which at present prevails. The facts are against the "must be" of Pope. There was a time when other creatures were, and man was not, and when animated nature was able to dispense with the human race. Infinite wisdom must form the best possible system and a gradation of beings, which now includes man, is an actual part of the scheme. Pope's argument breaks down when, to justify the creation of man, he supposes that a chain of beings and an orderly universe could not have existed unless man had been a link in the series. His argument is equally weak when he maintains that the infinite wisdom of God is a guarantee that there will not be a gap in the endless chain of existences, but that it is a question whether infinite wisdom may not have made a mistake with respect to man's proper place in the series, and erred in the after sorting of the gradations which it had previously conceived and created on an infallible plan.[823] The poet was inconsistent to childishness. Johnson believed that when Pope talked of man's place he did not attach any meaning to the term. The words would seem to imply that it was a question whether man was placed in the circumstances which were best adapted to his moral, mental, and physical nature. But if Pope had thoroughly comprehended his borrowed phrases, he would not have proposed the enquiry under a form which stultified his premises.