I will consider the characterization of scientific expert trespassing testimony (henceforth ‘trespassing testimony’) by taking a step back. In particular, I will consider what type of philosophical project it is to attempt a characterization of a phenomenon such as trespassing testimony. I will argue that this methodological discussion has important consequences for both the characterization of trespassing testimony and for the diagnosis of its ramifications. Indeed, I will exemplify this by considering some criticism of my 2018 characterization and by comparing it to Ballantyne’s 2019 characterization. I will also address some accounts that appear to presuppose that trespassing testimony is invariably epistemically and ethically bad. Finally, I will begin to consider philosophical trespassing testimony. It turns out that while it may be as problematic as scientific expert trespassing testimony, it is harder to characterize. Moreover, it is harder to specify the circumstances under which the epistemic and moral consequences of philosophical trespassing testimony are negative or positive.

People are more inclined to see epistemic trespassing as a problem for others than for themselves. Consider how the term is used to denigrate opponents or disciplinary outsiders more frequently than to atone for one’s own epistemic sins. But we argue that it is in fact easier from the first-person perspective to know when one is trespassing than when others are. At bottom, knowing that someone is trespassing is not straightforward whenever we lack expertise in a relevant domain. We suggest some principles that can help us identify when a person—oneself or someone else—is trespassing epistemically.

In discussions about public trust in science, one often hears calls for more direct engagement between scientists and citizens. Such engagements, however, bring their own ethical challenges. One is how scientists can avoid overstepping the boundaries of their expertise (“epistemic trespassing”), another is the challenge of individual scientists coming to play a role as spokespeople for “science”, or a particular field of science, and thereby almost by necessity drawing on the academic work of others, without always being able to acknowledge it appropriately. These problems are intertwined with another form of “trespassing”: the ethical intricacies of trespassing into sources of authority other than the authority of the scientific expert, e.g. charismatic or traditional authority understood in a Weberian sense. I suggest that solutions to these problems need to be context sensitive, but that at least in some cases, the most ethical thing for individual scientists is to not communicate directly with the public, but rather to see this as a team task to which they should contribute indirectly.