 Finally, philosopher Nancy Cartwright (1983, 1994, 1999) has defended over several decades a thorough-going “patchwork” or pluralistic understanding of the relation between the sciences, as an alternative to the sort of “physics-at-the-bottom”, asymmetrical hierarchy common to weak emergentists and reductionists alike. She argues that close consideration of scientific practice suggests that fundamental physical laws hold only in certain artificial contexts limited to small-scale systems, which systems are maintained by macroscopic barriers and mechanisms serving to screen off “downward” causal effects. She suggests that such carefully contrived results can give us no reasonable confidence in a vision on which all of natural reality is fixed by the unfolding of bottom-up physical laws alone. While arguing in somewhat different ways, Dupré (1993) is sympathetic to the general pluralist or “anti-fundamentalist” thrust of Cartwright’s perspective. More generally, if anything like Cartwright’s view is correct, and the right ontological characterization of the underlying pluralism is one according to which there is fundamental novelty across the spectrum of natural reality, one might naturally take strong emergence to be much more prevalent than even its proponents have usually assumed. This perspective has affinities to the “transformational” accounts of emergence noted in  section 4.2.4.  For discussion of the broad issues raised by Cartwright, see Cat (1998) and entry on  the unity of science,  Section 5.