2017 Report on Consciousness and Moral Patienthood | Open Philanthropy Project

We aspire to extend empathy to every being that warrants moral concern … “In general, which types of beings merit moral concern?” Or, to phrase the question as some philosophers do, “Which beings are moral patients?”

For this preliminary investigation, I focused on just one commonly endorsed criterion for moral patienthood: phenomenal consciousness, a.k.a. “subjective experience.”

Source: 2017 Report on Consciousness and Moral Patienthood | Open Philanthropy Project, by Luke Muehlhauser
* Notice: approximately 139,000 words, 347 pages, 9 appendices, 422 footnotes *

Let me be clear, then, that I am not a specialist on these topics. This report is long not because it engages its subject with the depth of an expert, but because it engages an unusual breadth of material — with the shallowness of a non-expert.

my more modest goals for this report are to:

  1. survey the types of evidence and argument that have been brought to bear on the distribution question,
  2. briefly describe example pieces of evidence of each type, without attempting to summarize the vast majority of the evidence (of each type) that is currently available,
  3. report what my own intuitions and conclusions are as a result of my shallow survey of those data and arguments,
  4. try to give some indication of why I have those intuitions, without investing the months of research that would be required to rigorously argue for each of my many reported intuitions, and
  5. list some research projects that seem (to me) like they could make progress on the key questions of this report, given the current state of evidence and argument.


I focused on finding out whether I could convince myself of any non-obvious substantive claims about the distribution of consciousness.

Presumably a cognitively unimpaired adult human is a moral patient, and a rock is not. But what about … ?

Such questions are usually addressed by asking whether a potential moral patient satisfies some criteria for moral patienthood. Criteria I have seen proposed in the academic literature include:

  • Personhood or interests. (I won’t discuss these criteria separately, as they are usually composed of one or more of the criteria listed below.)
  • Phenomenal consciousness, a.k.a. “subjective experience.” See the detailed discussion below.
  • Valenced experience: This criterion presumes not just phenomenal consciousness but also some sense in which phenomenal consciousness can be “valenced” (e.g. pleasure vs. pain).
  • Various sophisticated cognitive capacities such as rational agency, self-awareness, desires about the future, ability to abide by moral responsibilities, ability to engage in certain kinds of reciprocal relationships, etc.
  • Capacity to develop these sophisticated cognitive capacities, e.g. as is true of human fetuses.
  • Less sophisticated cognitive capacities, or the capacity to develop them, e.g. learning, nociception, memory, selective attention, etc.
  • Group membership: e.g. all members of the human species, or all living things.

Note that moral patienthood can be seen as binary or scalar, and the boundary between beings that are and are not moral patients might be “fuzzy”.

it seemed that the four most important factors influencing my “wild guess” probabilities were:

  1. evolutionary distance from humans (years since last common ancestor),
  2. neuroanatomical similarity with humans,
  3. apparent cognitive-behavioral “sophistication” (advanced social politics, mirror self-recognition, abstract language capabilities, and some other PCIFs [potentially consciousness-indicating features]), and
  4. total “processing power” (neurons, and maybe especially pallial neurons).