Nature’s immanence is an ancient and intuitive idea. But it was at odds with the Platonic and Pythagorean philosophies, which insisted that reality must accessible to a rational mind, whose order is forcibly imposed upon a chaotic or amorphous substratum. It is the Ideal that is ultimately “real.” Accordingly, the apparent reality of nature is derivative and not immanent. From that perspective, the resistance of physical reality to the impositions of thought and action renders the natural world at best imperfect, at worst evil. This idea appealed to the Christian and Muslim mind, for which the reality and properties of nature depended entirely on divine will. The significance of the natural world for medieval Christians lay in being a divine creation, the venue for the spiritual journey, and a “book” to read like scripture for spiritual guidance. This mindset continued into the modern era to influence scientific ideas about nature. Non-living matter, at least, was considered passive, subject to rational analysis because it was essentially no more than a (divine) product of definition in the first place. The derivative reality of nature implies that the mathematical laws of nature could be considered transcendent, if not divinely decreed. They exist somehow a priori and apart from the universe itself. The immanent reality of nature, however, implies that laws of nature are not transcendent; they do not exist independently of matter. They are neither immutable nor governing. Not only the details, but the laws too must be immanent in matter, not imposed on it externally either by God of the theorist. The apparent universality and constancy of physical laws, for example, is an empirical finding, not a necessary or transcendent truth. The laws themselves are no more than compact expressions of empirical findings, not directives that matter must obey, like a computer obeys lines of programming code.