The _Philosophic Letters_ paint the struggles of an ardent, enthusiastic, inquisitive spirit to deliver itself from the harassing uncertainties, to penetrate the dread obscurity, which overhangs the lot of man. The first faint scruples of the Doubter are settled by the maxim: 'Believe nothing but thy own reason; there is nothing holier than truth.' But Reason, employed in such an inquiry, can do but half the work: she is like the Conjuror that has pronounced the spell of invocation, but has forgot the counter-word; spectres and shadowy forms come crowding at his summons; in endless multitudes they press and hover round his magic circle, and the terror-struck Black-artist cannot lay them. Julius finds that on rejecting the primary dictates of feeling, the system of dogmatical belief, he is driven to the system of materialism. Recoiling in horror from this dead and cheerless creed, he toils and wanders in the labyrinths of pantheism, seeking comfort and rest, but finding none; till, baffled and tired, and sick at heart, he seems inclined, as far as we can judge, to renounce the dreary problem altogether, to shut the eyes of his too keen understanding, and take refuge under the shade of Revelation. The anxieties and errors of Julius are described in glowing terms; his intellectual subtleties are mingled with the eloquence of intense feeling. The answers of his friend are in a similar style; intended not more to convince than to persuade. The whole work is full of passion as well as acuteness; the impress of a philosophic and poetic mind striving with all its vast energies to make its poetry and its philosophy agree. Considered as exhibiting the state of Schiller's thoughts at this period, it possesses a peculiar interest. In other respects there is little in it to allure us. It is short and incomplete; there is little originality in the opinions it expresses, and none in the form of its composition. As an argument on either side, it is too rhetorical to be of much weight; it abandons the inquiry when its difficulties and its value are becoming greatest, and breaks off abruptly without arriving at any conclusion. Schiller has surveyed the dark Serbonian bog of Infidelity: but he has, made no causeway through it: the _Philosophic Letters_ are a fragment.