In Defence of the Agent and Patient Distinction: The Case from Molecular Biology and Chemistry

Abstract

Philosophers, tracing back to Aristotle, traditionally distinguished between agents and patients in causal interactions. Agents interact with patients and patients suffer change as a result.Recently, many philosophers have challenged the agent/patient distinction, arguing instead that causal interactions are symmetrical, consisting in mutually interacting entities. Hence, they also argue that there is no principled basis for the agent/patient distinction.In this paper, I defend the distinction. I do so by arguing that there is a widespread type of causal interaction between distinct entities where an asymmetry results due to the interaction, providing principled grounds for the agent/patient distinction. The type of interaction is when one of the two (or more) interacting entities undergoes a change in its kind membership, structure, causal powers, or intrinsic properties as a result of the interaction, while the other does not. There are many examples of this type of interaction in molecular biology and chemistry. I focus specifically on (i) the actions of enzymes on substrates and (ii) H2O molecules breaking polarized molecules' bonds.After giving a brief overview of previous and historically important accounts of the agent/patient distinction, I present the critics' arguments. I then turn to the positive case, arguing that there are many interactions resulting in an asymmetry that provides a principled basis for distinguishing agents from patients. Finally, I lay out and to a limited extent defend several commitments of my account and respond to objections. Part 1 Agent and Patient Distinction Overview I'll start with an initial characterization of previous accounts of the agent/patient distinction before turning to criticisms of it in Part 2. I'll then defend a nuanced version of the distinction in