The immortality of the soul, for me, following Maimonides, consisted in the union with the Universal Spirit of that part of the faculty of knowledge which has been brought into exercise, in proportion to the degree of that exercise; and in accordance with this doctrine I held those only to be partakers of this immortality, who occupy themselves with the knowledge of eternal truths, and in the degree in which they do so. The soul, therefore, must, with the attainment of this high immortality, lose its individuality. That Mendelssohn, in accordance with modern philosophy, thought differently on this subject, every one will readily believe. His sentiments in reference to revealed or positive religion I can give here, not as something made known to me by himself, but merely in so far as I have been able to infer them from his utterances on the subject in his writings with the assistance of my own reflections. For at that time, as an incipient freethinker, I explained all revealed religion as in itself false, and its use, so far as the writings of Mendelssohn had enabled me to understand it, as merely temporary. Moreover, being a man without experience, I thought it an easy matter to convince others in opposition to their firmly rooted habits and long-cherished prejudices, while I assumed the usefulness of such a reformation to be undoubted. Mendelssohn therefore was unable to hold any conversation with me on the subject, since he could not but fear lest, as has happened, and happens still, in the case of several others, I should pronounce his arguments in reply to be mere pieces of sophistry, and should attribute motives to him on that account. From his utterances, however, in the preface to his _Manasseh ben Israel_ as well as in his _Jerusalem_, it is clear that, though he did not consider any revealed _doctrines_ to be eternal truths, yet he accepted revealed laws of religion as such, and that he held the laws of the Jewish religion, as the fundamental laws of a theocratic constitution, to be immutable as far as circumstances allow.