The problem of explaining shifting targets

Sometimes we try to explain one thing but end up explaining something else. In this paper, I address when this is a problem, which I call the “Problem of Explaining Shifting Targets” (PEST). In PEST, the explanatory target shifts to another, where the original and shifted targets are manifestly different. Nonetheless, the explaining is treated as for the original target or one equivalent to it, as the agent does not recognize the change. Through the analysis of three candidate cases of PEST, I address the conditions under which it occurs. Further, I address three factors—agents are interested in the target they start with, which then shifts, but they do not recognize it—that capture why PEST should not be all that surprising. PEST is thus an error that makes salient that we must reflect on the dynamic relations between explanation and its target. Because it is subtle, PEST is insidious. It involves appeals to good evidence, and there may be no clear marker that someone has erred. Likewise, it is consequential. Shifts can wreak havoc on a research program or lead to people defending targets that they should not.