Multilevel Reality, Mechanistic Explanations, and Intertheoretic Reductions

Abstract

In the first part of this paper, I argue that what we consider to be a “mechanism,” “level,” or “component” depends on the perspectives that scientists have explicitly or implicitly adopted. If this is right, interlevel explanations and intertheoretic reductions become intimately connected. That is, I show that we cannot make sense of competing interlevel explanations of the same phenomena without reference to how those different levels of analysis relate or reduce to one another. And likewise, we cannot make sense of intertheoretic reductions (e.g., Newtonian to Relativistic equations of motion) without reference to how explanations of the same phenomena produced by those different perspectives compare. To better understand this connection between interlevel explanations and intertheoretic reductions a distinction is drawn in the second half of this paper, though only provisionally, between strong and weak relations. In the end, this distinction is removed as it only suggests ideals which are never reached in practice. Nevertheless the distinction helps us to understand how scientists can relate multiple perspectives to one another and also why they should always ultimately try to seek out newer, wider and deeper perspectives. In the end, I argue that how to relate interlevel explanations and complete theoretical reductions in science cannot be answered in the abstract by purely philosophical considerations, but only with reference to, and in accordance with, the actual history and practice of science. This is true not only for physical, but also for all empirical theories, something I show with a brief example from current cancer research.