Can mechanistic explanation be reconciled with scale-free constitution and dynamics?

• Biological systems are often scale-free in both space and time; hence they lack well-defined boundaries.
• Imposing boundaries to identify mechanisms is an idealizing heuristic employed by scientists.
• When successful it results in mechanistic explanations that can account for phenomena to a first approximation.
• To improve upon such first approximations, researchers can extend mechanism boundaries.
• But the revised mechanistic explanations still remain idealizations.

This paper considers two objections to explanations that appeal to mechanisms to explain biological phenomena. Marom argues that the time-scale on which many phenomena occur is scale-free. There is also reason to suspect that the network of interacting entities is scale-free. The result is that mechanisms do not have well-delineated boundaries in nature. I argue that bounded mechanisms should be viewed as entities scientists posit in advancing scientific hypotheses. In positing such entities, scientists idealize. Such idealizations can be highly productive in developing and improving scientific explanations even if the hypothesized mechanisms never precisely correspond to bounded entities in nature. Mechanistic explanations can be reconciled with scale-free constitution and dynamics even if mechanisms as bounded entities don't exist.