For something to be a law, man must be able to recognize it and say ‘yes;’ for something to be natural, man must hear it straight from nature’s voice.
Hence disregarding all the scientific books that only teach us to see men as they have made themselves, and meditating on the first and simplest operations of the human Soul, I believe I perceive in it two principles prior to reason, of which one interests us intensely in our well-being and our self-preservation, and the other inspires in us a natural repugnance to seeing any sentient Being, and especially any being like ourselves, perish or suffer. It is from the cooperation and from the combination our mind is capable of making between these two Principles, without it being necessary to introduce into it that of sociability, that all the rules of natural right seem to me to flow; rules which reason is subsequently forced to reestablish on other foundations, when by its successive developments it has succeeded in stifling Nature.
This way one is not obliged to make a Philosopher of man before making a man of him; his duties toward others are not dictated to him exclusively by the belated lessons of Wisdom; and as long as he does not resist the internal impulsion of commiseration, he will never harm another man or even any sentient being, except in the legitimate case when, his preservation being involved, he is obliged to give himself preference.