Nietzsche describes "der letzte Mensch" as the lowest form of human life. His scientific materialism is the most degrading, smallest illusion, worse than any religious dogma. The last man has regressed to the thoughts of what we used to call "beasts," that is, life which is concerned with, can only understand, biological sustenance. Even that may be overly generous, as beasts can be at least curious. His religion, such as it is, is survival, or, at the most, health.

He is not so much scientific as scientistic. Science, understood as a type of mathematical empiricism, is not metaphysical. Empirical rigor prevents the authentic scientist from making claims about the existence of God or the proper ends of human life -- or about science itself. When one's gaze turns from the empirically quantifiable to examine the scientific method itself, one has started doing philosophy. One cannot look through the microscope and look at the microscope at the same time.

The idea that science is a metaphysical system rather than a method for modeling the world mathematically is scientism. Scientism makes claims that are not susceptible to mathematical analysis or reproducible experiments; that is what distinguishes it from science. These claims include: the world as perceived by human senses is the primary or ultimate reality; science is the best way of understanding the world; God (the Hebraic, infinite God) does not exist; health (understood as reproductive fitness) is the primary object and standard of value of human life. These are all metaphysical or moral claims and as such do not describe objects in the world or physical matter that can be examined by the scientific method.

Scientism leads naturally to pseudo-science. If you believe in scientism, then you believe that "science" can provide answers to metaphysical and moral questions. If you believe that, then you believe things like <a href="http://www.sciencedaily.com/releases/2013/12/131217210540.ht... are scientific, rather than pseudo-science. It is pseudo-science because it is based on beliefs concerning what is better as the end of life. Such beliefs are not susceptible to mathematical modeling and are therefore not part of science.

Pseudo-science leads to progressivist political ideologies. Karl Marx is merely the most infamous proponent of "scientific materialism," his term for a baroque and metaphysical religion. It is a religion, based on scientistic historical analysis, atheism, and economics as the valuation of human flourishing. Following the disastrous horrors of the Soviet and Maoist experiments, few today openly fly the Communist banner, but similar ideals persist in more subtle forms.

Progressivism, because it is inherently a metaphysical system based on mythological pseudo-science, views Christianity as infidels. As in Islam, the infidel is sometimes tolerated, sometimes more aggressively attacked. Militant atheism distinguishes itself from science by, again, making metaphysical claims about the nature of reality instead of mathematically modeling certain phenomena, and further by enacting legislation (or more thug-like vigilantism) enshrining its particular mythology (scientism). The infidel, as again in Islam, is not argued with but attacked in a jihad, whether through official legislation or "activism."