The difficulties which Milton felt and conquered in the making of his epic masterpiece had their origin, for the most part, in the intractable and barren nature of his chosen theme. The dangers that beset him, and sometimes tripped his feet, arose, on the other hand, from his own declared intention in the handling of that theme:-- That, to the highth of this great argument, I may assert Eternal Providence And justify the ways of God to men. The pursuit of this argumentative end led him through strange passes. A less courageous or a more sensitive man might well have hesitated at the entrance. But Milton hesitated at nothing. The ultimate mysteries of human existence and Divine government were no mysteries to him. The living Throne, the sapphire blaze, Where angels tremble, while they gaze, He saw; --and he did not tremble. His persons are visible, their characters are known, the nature of their relations is easily ascertained and expounded. Everything, in short, is as plain as a pikestaff. So he came to picture scenes which criticism is reluctant to traverse, and to make statements which it is equally irreverent either to affirm or to deny. Dr. Johnson, with a fearful and sincere piety, refused to follow Milton into Heaven. "Of the agents in the poem," he says, "the chief are such as it is irreverence to name on slight occasions." And again:--"The characters in the _Paradise Lost_ which admit of examination are those of angels and of man." It is impossible not to respect Johnson's attitude, but later critics have found it difficult to follow his example, and Milton himself would have been the last to claim sanctuary in Heaven for the imaginations on which the whole fabric of the poem depends.