Suffering is the experiencing of unpleasant qualia by a conscious being. If we disregard mental suffering (which can complicate matters infinitely) and restrict ourselves to physical suffering, then it can be described completely by unpleasant qualia in the CBS. Examples would be a pin-prick on a finger to a pounding headache or even a bad odor.
Which then leads us to a question as to whether identical suffering (measured strictly on the qualia scale) experienced by two different beings are actually given the same recognition by neutral observers.
In other words, is John's pain from a pin-prick identical to that of Jane's? If we feel empathy for John or Jane because pain is felt by John or Jane, can we make the perceiver irrelevant and feel empathy just because pain is felt?
Clearly, the answer to the above is negative for the vast majority of people. We may feel empathy for our friends, or even our pets, but most of us don't think that way when we are dealing with roaches or rats in our homes.
Since there has not been any scientific explanation for qualia yet, it is not known whether rats and roaches can feel the same degree of pain as humans. Many biologists assume that they cannot because of their simpler brain architectures, but since we know nothing about what it feels to be like a rat or a bat, the truth could be anybody's guess.
Complicating matters further is the point of view adopted by many religions (and also advanced civilizations) that even if we assume that lower forms of life experience the same or even more intense pain, they don't matter as much as higher forms like humans (as well as their pets).
This is why families would grieve for a long time over their pet dog getting run over by a car, but would not think twice about the hundreds of cows or pigs slaughtered over the course of years to feed themselves as well as their dog.
Some of this is also cultural. A Chinese national may consider the slaughter of dogs for meat no different from that of cattle, but many Westerners will find it inhumane and disgusting.
It therefore seems that there are several inconsistencies in the recognition of suffering by another conscious entity. If we are to break ground in the theory of qualia someday, we need to resolve these kinds of inconsistencies in empathy and ethics. Since all religions deal with these issues, it is quite clear that this should be of paramount importance, at least in the theory of meta-ethics.
If we put aside these inconsistencies and go back to the first question, can we disregard the perceiver and accord empathy to any being that perceives the same degree of pain as John or Jane?
The simplest example will be a CBS with just the sensation of a pin-prick somewhere in it. But, according to my previous post, every qualia is a self-contained perception, which means that it brings with it its own CBS (in other words, the perceiving agent). So, we can actually go on to claim that 'a pain quale' in itself should elicit the same amount of empathy as John or Jane who feels an equivalent sensation. This would be a really condensed version of empathy, which could be taken as a fundamental axiom, corresponding to certain sets of qualia.
I also would like to reiterate that empathy will be a fundamental construct in the theory of qualia, and not something that is 'nice' or having a purely theological or moral appeal.
Only some qualia will elicit empathy - for example, a pin-prick, but not a point source of blue light. These should be rigorously derived from the theory of qualia.
One complication is the non-linearity of perceived qualia- music played at a soft volume should not elicit empathy, but that at deafening volumes should. The latter is a form of torture and has been used against prisoners.
But I suspect that the perceived non-linearities have more to do with the architecture of the human brain and not with qualia themselves. As I have postulated here, qualia are extremely linear.