Phenomenal consciousness: subjective experience, there is “something that it is like” to be that entity.
Sentience: a specific subset of phenomenal consciousness, subjective experiences with positive or negative valence. Pleasures like bodily pleasures and contentment have positive valence, and displeasures like pain or sadness have negative valence.
Agency: having desires or preferences, goals one is aiming to achieve.
Sentience linked to agency: As you’ve no doubt noticed, your good or bad experiences (sentience) are usually accompanied by preferences and desires (agency): stubbing your toe feels bad and you don’t want this bad feeling; massages feel good and you want that good feeling. On the flip side, having your preferences and desires (agency) thwarted leads to conscious experiences of frustration, sadness, and anger (sentience); having your preferences and desires satisfied leads to conscious experiences of satisfaction, happiness, and contentment.
Consciousness linked to sentience: It’s plausible that every animal that has subjective experiences in general (phenomenal consciousness) has experiences of pleasure and pain in particular (sentience): pain and pleasure are ancient and crucial biological adaptations, so it’s plausible that whenever consciousness shows up in the tree of life, pleasure and pain are already there to be consciously experienced.
Various thought experiments ask the reader to consider hypothetical entities that decouple consciousness, sentience, and agency.
Consciousness and agency without sentience: Chalmers’s Vulcans
A Vulcan is, in Chalmers’s words, “a conscious creature that experiences no happiness, suffering, pleasure, pain or any positive or negative affective states”, but still has desires and preferences and (per “conscious”) complex experiences. Chalmers argues that Vulcans have moral standing; his intuition is that even without valenced experience, Vulcans matter.
Consciousness without agency or sentience: Chalmers’s “more extreme” Vulcans
A ‘more extreme’ Vulcan is, in Chalmers’s words, a Vulcan that is “indifferent to continuing to live or dying”, lacking agency as well. Chalmers holds that even these creatures still have some moral standing, because “more than affective consciousness and desire satisfaction matter” for moral standing.
Agency without consciousness or sentience: Kagan’s (2019) alien robots.
AI systems may occupy very different locations in the “space of possible minds
Not knowing much about it I can imagine different Vulcans, non-sentient Vulcans to have moral standing. Also I can imagine that different subjects may varying depth of consciousness, sentience, agency.
However, It is hard for me imagine that agency itself can create moral standing (from quoted Kagan’s thought experiment). Would agentic machines include any machine that does something? Would this include a wind mill? Does a car that is programmed to accelerate at a random hour would be included in that group? Perhaps the crux is in “desiring” to do something – but desiring by itself seems part of phenomenal consciousness.
It would be interesting how much human and non-human animals plot on the three vectors of moral standing. I can imagine a person that has varying degrees/strengths of: phenomenal consciousness (a mediator who is focused on experience), sentience (some people may be more affected by the positive and negative valence), agency (there are are people who want more and there are people who are more passive).