The basic point of the essay by a philosopher is that scientists maker metaphysical judgments all the time:-http://nautil.us/issue/29/scaling/why-science-needs-metaphysics-What then has to be the case for genuine science as such to be possible? This is a question from outside science and is, by definition, a philosophical—even a metaphysical—question. Those who say that science can answer all questions are themselves standing outside science to make that claim. That is why naturalism—the modern version of materialism, seeing reality as defined by what is within reach of the sciences—becomes a metaphysical theory when it strays beyond methodology to talk of what can exist. Denying metaphysics and upholding materialism must itself be a move within metaphysics. It involves standing outside the practice of science and talking of its scope. The assertion that science can explain everything can never come from within science. It is always a statement about science.-***- Science has a universal reach. A scientific discovery about the character of the universe should be one that notional scientists in far-off galaxies could share. The physical laws at least of our own universe remain constant and are intelligible anywhere in it. This gives a clue to a basic fact about science that is often taken for granted by working scientists. Science investigates an objective reality open to all and independent of mind.-***-Mathematics, though, could be claimed to be merely a tool created by the human mind. Why, then, should we assume that it can express in compressible form the workings of physical reality? Those, like Max Tegmark, who assume that the nature of reality is mathematical are making a jump between symbols that seem to be the creation of mind and a reality that not only exists independently of our knowledge of it but also far outstrips any possible knowledge. Tegmark explains the utility of mathematics for describing the physical world as “a natural consequence of the fact that the latter is a mathematical structure, and we're simply uncovering this bit by bit.” However, this is itself a metaphysical statement about the nature of reality, logically preceding the conduct of physics.-***-There is such a thing as scientific progress, and it happens through systematic trial and error or, in Karl Popper's terminology, conjecture and refutation. A “scientific realist” has to be wary, though, about how such realism is defined. A realism that makes reality what contemporary science says it is links reality logically to the human minds of the present day. Science is then just a human product, rooted in time and place. Bringing in future science—or ideal science—may sound more plausible, but even then there is a distinction between science reflecting (or corresponding to) the nature of reality and it being simply a human construction. Once the logical independence of reality from science is accepted, the question is why reality has a character that enables it to be understood scientifically. The intelligibility and intrinsic rationality of reality cannot be taken for granted. Even the greatest scientists, such as Einstein, have seen that the intelligibility of the world is a mystery. He famously remarked that “the eternally incomprehensible thing about the world is its comprehensibility.” Like the way in which mathematics seems to map the intrinsic rational structure of the physical world, this is presupposed within science and cannot be given a scientific explanation. It appears to be a metaphysical fact, and the explanation for which, if there can be one, must come from beyond science.-Comment: Multiverse conjecture out the window!