The Comprehensibility of the Universe puts forward a radically new conception of science. At present scientific enquiry is shaped by the orthodox view that in accepting or rejecting theories scientists are impartial with respect to evidence and make no permanent assumptions about the world independently of the evidence. Nicholas Maxwell argues that this view is untenable, and that we need a new orthodoxy, which sees science as making a hierarchy of increasingly attenuated metaphysical assumptions about the comprehensibility and knowability of the universe. This new conception has significant implications, as Maxwell explains. One is that it is part of current scientific knowledge that the universe is comprehensible, even physically comprehensible. A second is that metaphysics and philosophy are central to scientific knowledge. A third is that science possesses a rational, though fallible, method of discovery. A fourth is that we need a new understanding of scientific method and rationality. Maxwell points the way towards the solution, within his new conception, of long-standing philosophical problems about science, concerning simplicity, induction, and progress. His goal is the reform not just of the philosophy of science but of science itself, and the healing of the rift between the two.