To enlarge his mind, to exalt his imagination, and to enrich his eloquence, Torquato now devoted much of his attention to the works of Aristotle and Plato; but while the former subjected his reason to the severest discipline in the ascertainment of principles of truth, he gave his whole soul to the guidance of the latter, whose visionary splendour and profound speculations, on subjects the highest that created intelligences can conceive, and of which comparatively so little can be learned without "light from heaven" to illumine the "light of nature,"--while infinite space is afforded for everlasting conjectures, showing at once the capabilities and the limitations of the human intellect,--these peculiarly suited the young student's cast of thought and intense delight in contemplating the things that are invisible and eternal, as associated with things seen and perishable. Nor was the philosophical poet an unworthy disciple of the poetical philosopher, even upon his own ground and in his own style. Many of Tasso's sublimest compositions are in the form of dialogues, in which he discourses with an elevation of sentiment and a power of diction which might have gained admiration in the school of his master himself.
Meanwhile the germ of his great poem, which had been quickened, probably not later than the publication of the "Rinaldo," was growing up in his thought,--for Tasso, by the necessity of his nature, was ever ruminating on some premeditated or progressive theme; and some mightier conception followed the disburdenment of every matured production of his inexhaustibly inventive genius. While this new and magnificent project was gradually assuming shape and character before he entered upon the deliberate execution of it, he prepared himself for the task by composing his "Discourses on Heroic Poetry," which place him among critics in as high a rank as that which he holds among poets. The merit of these essays, indeed, is so remarkable, that his principal English biographer, Mr. Black, is almost seduced by them to assert the universality of the author's genius, in the following plausible remark and happy quotations from high authority concerning another extraordinary poetic genius, which seemed capable of excelling in whatever it undertook, whether in prose or rhyme:--"Of the 'Discourses on Heroic Poetry' there appear to have been four, only three of which have been printed. Though composed at the age of twenty, and published without the knowledge and corrections of the author, they are exceedingly valuable; and while they display a most refined taste, discover also much metaphysical acuteness and geometrical precision. Indeed, I am more and more of opinion that what Mr. Stewart says of Burns is true in general of every great poetical genius, 'All the faculties of Burns's mind,' says he, 'were, as far as I could judge, equally vigorous; and his predilection for poetry was rather the result of his own enthusiastic and impassioned temper, than of a genius exclusively adapted to that species of composition.'"