On the issue of feelings and experience, if we define feelings in the broader sense of simply “being affected by” or “responding to”, if we consider a feeling to be nothing more than the fact that the organism or entity in question is changing and responding to something and that the “feeling” is simply this “responding to” as such, then we might be tempted to say that everything is potentially feeling. But I would pair feelings, even in this broadest definition, with what I just described as the basis for experience, namely subjectivity or having a perspective:
If an entity has subjectivity, which means is having an active experience (as I outlined above in the previous post), then the “feelings” (respondings-to) of that entity can be considered to be true feelings as we typically understand them, because the organism is “feeling” itself to itself, it is experiencing its own responses, responding to its own responses as an experience. If this is what it means to feel, in contradistinction to simply “responding to” as such, then I think we have a basis here for defining sentience more precisely: sentience is the case when an entity possesses subjectivity (is at least minimally phenomenologically capable) therefore converting its rudimentary responses and respondings-to into an experience of those responses, a responding to its own responses.
And how would it experience in this way? What would the experience of a feeling be like? We already know this from our own experiences with our own feelings, and we can rationally posit that feelings for any sentient organism would be similar, namely they would be like forces generated within the organism and against the organism itself, they would be experienced like “pressures” within the organism itself that have either a desirable, undesirable (or perhaps also neutral (in terms of desirability)) quality, namely the pressure compels us either toward or away from itself, which means toward or away from that which is causing the pressure. In terms of subjectivity or consciousness and our experience of it, the feeling is like a force imposed on the experiencing entity from the outside, that is how it is experienced by that entity, even though the feeling is actually generated within the entity itself.