In discussion with a reasoner who held stubbornly to a system once adopted Mendelssohn was stubborn himself, and took advantage of the slightest inaccuracy in his opponent's way of thinking. On the other hand, with a more accommodating thinker he was accommodating also, and used commonly to close the discussion with the words, "We must hold fast, not to mere words, but to the things they signify."
Nothing was so offensive to him as an esprit de bagatelle or affectation; with anything of this sort he could not conceal his displeasure. H—— once invited a party, in which Mendelssohn was the principal guest, and he entertained them the whole time with talk about some hobby of his, which was not exactly of the choicest kind. Mendelssohn showed his displeasure by never deigning to give the slightest attention to the worthless creature. Madam —— was a lady who affected an excess of sensibility, and as is customary with such characters, used to reproach herself in order to extort praise from others. Mendelssohn sought to bring her to reason by showing her impressively how exceptionable her conduct was and how she ought to think seriously about improvement.
In a disconnected conversation he took little part himself; he acted rather as observer then, and took pleasure in watching the conduct of the rest of the company. If, on the other hand, the conversation was coherent, he took the warmest interest in it himself, and, by a skilful turn, he could, without interrupting the conversation, give it a useful direction.
Mendelssohn could never take up his mind with trifles; matters of the greatest moment kept him in restless activity, such as the principles of Morals and of Natural Theology, the immortality of the soul, etc. In all these branches of inquiry, in which humanity is so deeply interested, he has also, as I hold, done as much as can be done on the principles of the Leibnitio-Wolfian philosophy. Perfection was the compass which he had constantly before his eyes, and which directed his course, in all these investigations. His God is the Ideal of the highest perfection, and the idea of the highest perfection lies at the basis of his Ethics. The principle of his Æsthetics is sensuous perfection.
My discussion with him on our first acquaintance referred mainly to the following points. I was a faithful adherent of Maimonides before I became acquainted with modern philosophy; and, as such, I insisted on the negation[55] of all positive attributes to God, inasmuch as these can be represented by us only as finite. Accordingly I proposed the following dilemma: Either God is not the absolutely perfect being, in which case his attributes may by us be not only conceived, but also known, that is, represented as realities belonging to an object; or He is the absolutely perfect being, and then the idea of God is conceived by us, but its reality is merely assumed as problematic. Mendelssohn, on the other hand, insisted on the affirmation, with regard to God, of all realities,—a position which goes very well with the Leibnitio-Wolfian philosophy, because it requires, in order to prove the reality of an idea, nothing more than that it is thinkable, that is, fulfils the law of Non-Contradiction.
My moral theory was then genuine Stoicism. It aimed at the attainment of free will and the ascendency of reason over the feelings and passions. It made the highest destination of man to be the maintenance of his differentia specifica, the knowledge of the truth; and all other impulses, common to us with the irrational animals, were to be put in operation merely as means to this chief end. The knowledge of the good was not distinguished by me from the knowledge of the true; for, following Maimonides, I held the knowledge of the truth to be the highest good of man. Mendelssohn, on the other hand, maintained that the idea of perfection, which lies at the basis of Ethics, is of much wider extent than the mere knowledge of the truth. All natural impulses, capacities and powers, as something good in themselves (not merely as means to something good), were to be brought into exercise as realities. The highest perfection was the idea of the maximum, or the greatest sum, of these realities.
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.
So far as I am concerned, I am led to assent entirely to Mendelssohn's reasoning by my own reflections on the fundamental laws of the religion of my fathers. The fundamental laws of the Jewish religion are at the same time the fundamental laws of the Jewish state. They must therefore be obeyed by all who acknowledge themselves to be members of this state, and who wish to enjoy the rights granted to them under condition of their obedience. But, on the other hand, any man who separates himself from this state, who desires to be considered no longer a member of it, and to renounce all his rights as such, whether he enters another state or betakes himself to solitude, is also in his conscience no longer bound to obey those laws. I assent moreover to Mendelssohn's remark, that a Jew cannot, by simply passing over to the Christian religion, free himself from the laws of his own religion, because Jesus of Nazareth observed these laws himself and commanded his followers to observe them. But how, if a Jew wishes to be no longer a member of this theocratic state, and goes over to the heathen religion, or to the philosophical, which is nothing more than pure natural religion? How, if, merely as a member of a political state, he submits to its laws, and demands from it his rights in return, without making any declaration whatever about his religion, since the state is reasonable enough not to require from him a declaration with which it has nothing to do? I do not believe Mendelssohn would maintain that even in this case a Jew is bound in conscience to observe the laws of his fathers' religion merely because it is the religion of his fathers. As far as is known, Mendelssohn lived in accordance with the laws of his religion. Presumably, therefore, he always regarded himself as still a member of the theocratic state of his fathers, and consequently acted up to his duty in this respect. But any man who abandons this state is acting just as little in violation of his duty.
On the other hand I consider it wrong in Jews, who from family attachments and interests profess the Jewish religion, to transgress its laws, where, according to their own opinion, these do not stand in the way of those motives. I cannot therefore understand the conduct of Mendelssohn in reference to a Jew of Hamburg who openly transgressed the laws of his religion, and who was on that account excommunicated by the chief rabbi. Mendelssohn wanted to cancel the excommunication on the ground that the church has no rights in civil matters. But how can he then maintain the perpetuity of the Jewish ecclesiastical state? For what is a state without rights, and wherein consists, according to Mendelssohn, the rights of this ecclesiastical state? "How," says Mendelssohn, (in the preface to Manasseh ben Israel, p. 48), "can a state allow one of its useful and respected citizens to suffer misfortune through its laws?" Surely not, I reply; but the Hamburg Jew suffers no misfortune by virtue of the excommunication. He required only to say or do nothing which legally leads to this result, and he would then have avoided the sentence. For excommunication is merely tantamount to saying:—"So long as you put yourself in opposition to the laws of our communion, you are excluded from it; and you must therefore make up your mind whether this open disobedience or the privileges of our communion can most advance your blessedness." This surely cannot have escaped a mind like Mendelssohn's, and I leave it to others to decide how far a man may be inconsistent for the sake of human welfare.