 Second, some suggest a pragmatic-type argument to show that the Causal and Sufficient Reason principles are true, namely that the principles are necessary to make the universe intelligible. Without such principles, Pruss argues, science itself would be undercut. “Claiming to be a brute fact should be a last resort. It would undercut the practice of science” (Pruss 2006: 255). Utilization of the principles best accounts for the success of science, indeed, for any investigatory endeavor (Koons 1997; see also Koons 2008: 111–12, where he argues that it is “a subjectively required presumption needed for immunity to internal defeaters”). The best explanation of the success of science and other such rational endeavors is that the principles really indicate how reality operates.