In the writings of Cicero, accordingly, everything deduced from experience and knowledge of the world--every observation on the duties of society, is clearly expressed, and remarkable for justness and acuteness. But neither Cicero, nor any other Roman author, possessed sufficient subtlety and refinement of spirit, for the more abstruse discussions, among the labyrinths of which the Greek philosophers delighted to find a fit exercise for their ingenuity. Hence, all that required research into the ultimate foundation of truths, or a more exact analysis of common ideas and perceptions--all, in short, that related to the subtleties of the Greek schools, is neither so accurately expressed, nor so logically connected.
In theoretic investigation, then,--in the explication of abstract ideas--in the analysis of qualities and perceptions, Cicero cannot be regarded as an inventor or profound original thinker, and cannot be ranked with Plato and Aristotle, those mighty fathers of ancient philosophy, who carried back their inquiries into the remotest truths on which philosophy rests. Where he does attempt fixing new principles, he is neither very clear nor consistent; and it is evident, that his general study of all systems had, in some degree, unsettled his belief, and had better qualified him to dispute on either side with the Academics, than to examine the exact weight of evidence in the scale of reason, or to exhibit a series of arguments, in close and systematic arrangement, or to deduce accurate conclusions from established and certain principles. His philosophic dialogues are rather to be considered as popular treatises, adapted to the ordinary comprehension of well-informed men, than profound disquisitions, suited only to a Portico or Lyceum. They bespeak the orator, even in the most serious inquiries. Elegance and fine writing, their author appears to have considered as essential to philosophy; and historic, or even poetical illustration, as its brightest ornament. The peculiar merit, therefore, of Cicero, lay in the happy execution of what had never been before attempted--the luminous and popular exposition of the leading principles and disputes of the ancient schools of philosophy, with judgments concerning them, and the application of results, deduced from their various doctrines to the peculiar manners or employments of his countrymen. Hence, though it may be honouring Cicero too highly, to term his works, with Gibbon, a Repository of Reason, they are at least a Miscellany of Philosophic Information, which has become doubly valuable, from the loss of the writings of many of those philosophers, whose opinions he records; and though the merit of originality rests with the Greek schools, no compositions transmitted from antiquity present so concise and comprehensive a view of the opinions of the Greek philosophers(387).