Cancer beyond genetics: On the practical implications of downward causation

Discussions about reductionism and downward causation are often assumed to be primarily of interest to philosophers. Often, however, the question of whether multi-scale systems can be understood “bottom-up” has important practical implications for scientific inquiry. Cancer research, I argue, is one such example. While the focus on genetic factors has intensified with recent investments in cancer genomics, the importance of biomechanical factors within the tumor microenvironment is increasingly acknowledged. I suggest that role of solid-state tissue properties in tumor progression can be interpreted as a form of downward causation, understood as constraining relations between tissue-scale and micro-scale variables. Experimental demonstrations of these sort of influences reveal limitations of reductionist accounts and expose the dangers of what Wimsatt calls functional localization fallacies. The latter relate to the common bias of downgrading factors that – as a practical necessity – are left out of scientific analysis. Any heuristic, experimental or theoretical, involves foregrounding some aspects while ignoring others, and the complexity of cancer leaves room for the co-existence of many different partial perspectives. These perspectives are not reducible to one another, but neither do they in this case make up a neatly integrated “causal mosaic” of different influences. At present, the picture of cancer research looks more like a fragmented cubist painting in need of a more balanced attention to difference-making factors at higher levels or scales