Since reason demands nothing which is opposed to Nature, it demands, therefore, that every person should love himself, should seek his own profit--what is truly profitable to him--should desire everything that really leads man to greater perfection, and absolutely that every one should endeavor, as far as in him lies, to preserve his own being. This is all true as necessarily as that the whole is greater than its part. Again, since virtue means nothing but acting according to the laws of our own nature, and since no one endeavors to preserve his being except in accordance with the laws of his own nature, it follows: _Firstly_, That the foundation of virtue is that endeavor itself to preserve our own being, and that happiness consists in this--that a man can preserve his own being. _Secondly_, It follows that virtue is to be desired for its own sake, nor is there anything more excellent or more useful to us than virtue, for the sake of which virtue ought to be desired. _Thirdly_, It follows that all persons who kill themselves are impotent in mind, and have been thoroughly overcome by external causes opposed to their nature. Again, we can never free ourselves from the need of something outside us for the preservation of our being, and we can never live in such a manner as to have no intercourse with objects which are outside us. Indeed, so far as the mind is concerned, our intellect would be less perfect if the mind were alone, and understood nothing but itself. There are many things, therefore, outside us which are useful to us, and which, therefore, are to be sought. Of all these, none more excellent can be discovered than those which exactly agree with our nature. If, for example, two individuals of exactly the same nature are joined together, they make up a single individual, doubly stronger than each alone. Nothing, therefore, is more useful to man than man. Men can desire, I say, nothing more excellent for the preservation of their being than that all should so agree at every point that the minds and bodies of all should form, as it were, one mind and one body; that all should together endeavor as much as possible to preserve their being, and that all should together seek the common good of all. From this it follows that men who are governed by reason--that is to say, men who, under the guidance of reason, seek their own profit--desire nothing for themselves which they do not desire for other men, and that, therefore, they are just, faithful, and honorable. These are those dictates of reason which I purposed briefly to set forth before commencing their demonstration by a fuller method, in order that, if possible, I might win the attention of those who believe that this principle--that every one is bound to seek his own profit--is the foundation of impiety, and not of virtue and piety. _The Essence of Virtue_ I