French revolutionary philosophers and the socialist theoreticians who followed them in the early 1800s were captured by what British socialist Graham Wallas called the liberal fallacy: the self-absorbed assumption that whatever their reasoning told them had, by definition, to be the truth and, furthermore, that everyone else on earth would naturally agree with their conclusions. It is a form of tunnel vision that ignores all factors other than what interests liberals.
We see this today in the prescriptions of liberal Republicans and liberal Democrats. They are confident that, because they abhor war, so too does Al Queda. Because liberals are willing to relinquish our national sovereignty to the UN, confident that every dispute can be resolved by rational discussion, they assume Islamic jihadists are wired the same way.
At the apogee of atheistic materialism, in the 1830s, Auguste Comte's well-intentioned expectation was that all the world would quickly recognize the superiority of his Positivistic philosophy and its Religion of Humanity. People from the rest of Europe, from America, and from Asia, he assumed, would all come to sit worshipfully at his feet to learn the proper new system of socialist government and its canon of materialistic ethics.
Central to the process, of course, would be accepting the belief that there is no God other than human reason and that the proper object of worship is Man in the abstract, Humanity.