Things change, however, if you take more of a bare bones approach to reality. Perhaps reality is simply a distribution of "stuff", endowed with certain properties, through time and through space. What we call the laws of nature are then just patterns within this Humean mosaic (named after the philosopher David Hume). This is the idea behind best systems analysis, an approach developed largely by the American philosopher David Lewis in the second half of the twentieth century. Loewer likes this idea. And he thinks it may be attractive to physicists troubled by the question of how something abstract and outside of the Universe can govern the motions of bodies inside it.