Breaking with the Idealism of Plato, his thought, influenced by the Atomism of Democritus, was thoroughly materialistic in its description of the universe and — though its starting point was quite different — similar in many of its conclusions to that of the Stoics. The physical world, he held, was all there was and was composed of differently shaped atoms whose various combinations formed all matter; there were no divine laws or divine rewards or punishments for human actions, and hence no moral codes that human beings were obliged to obey. The only rational goal was to live life as pleasurably as possible.And yet, Epicurus wrote: “When we say that pleasure is the end and aim, we do not mean the pleasures of the prodigal or the pleasures of sensuality, as we are understood to do by some through ignorance, prejudice or willful misrepresentation. By pleasure we mean the absence of pain in the body and of trouble in the soul. It is not an unbroken succession of drinking bouts and of revelry, not sexual lust, not the enjoyment of the delicacies of a luxurious table, which produce a pleasant life…. We cannot live pleasantly without living wisely, honorably, and justly, nor live wisely, honorably, and justly without living pleasantly.”The more virtuous the life, in other words, the less vulnerable to physical suffering and mental agitation it is.
La Mettrie drew openly on this tradition, coming to think of his own thought as an “Epicurean” system, however partial that claim most certainly was… For La Mettrie was not only taking his scalpel to God and the soul; he was snipping the suture that had held Western intellectual life together since the time of Socrates: the link between virtue and human happiness; the link between happiness, reason and truth. Epicurus himself had not dared to go this far. In the Epicurean vision, reason—prudence—was the essential force that allowed one to distinguish between what would cause us pain and what would bring us true pleasure. Far from urging the expansion of desires, Epicurus advised us to limit them as strictly as we could. Bread and water were enough to feed the Epicurean sage. Happiness was virtue’s reward. Nor had Augustine, or Blaise Pascal, or any other Christian thinker inclined to mock the pretensions of reason in fallen man, dared to doubt that happiness and truth might not be linked. Reason was admittedly a limited guide. But in its awkward stumbling, it could lead us to the place where a guide more sure would help us on our way. The end of our journey was where happiness lay. In the Christian tradition, it was virtue, through the grace of God, that would take us there. La Mettrie denied these connections and, in doing so, helped make himself a pariah.…The festering problem remained: If human beings were moved solely, as the utilitarians argued, by sensations of pleasure and pain, then why individuals should sacrifice the one and endure the other for the sake of their fellow men was not at all clear. Despite Enlightenment insistence to the contrary, it was also not at all clear why virtue should always be pleasurable, why being good should be the same as feeling good.
The most general formula on which every religion and morality is founded is: “Do this and that, refrain from this and that — then you will be happy! Otherwise…” Every morality, every religion, is this imperative…Nobody is very likely to consider a doctrine true merely because it makes people happy or virtuous – except perhaps the lovely “idealists” who become effusive about the good, the true, and the beautiful and allow all kinds of motley, clumsy, and benevolent desiderata to swim around in utter confusion in their pond. Happiness and virtue are no arguments. But people like to forget – even sober spirits – that making unhappy and evil are no counterarguments. Something might be true while being harmful and dangerous in the highest degree. Indeed, it might be a basic characteristic of existence that those who would know it completely would perish, in which case the strength of a spirit should be measured according to how much of the “truth” one could still barely endure or to put it more clearly, to what degree one would require it to be thinned down, shrouded, sweetened, blunted, falsified. But there is no doubt at all that the evil and unhappy are more favored when it comes to the discovery of certain parts of truth, and that the probability of their success here is greater – not to speak of the evil who are happy, a species the moralists bury in silence.