Philosopher Eric Schwitzgebel argues that good philosophical arguments should be such that the target audience ought to be moved by the argument, but that such arguments are difficult to make regarding animal consciousness, since there is no common ground.
The Common Ground Problem is this. To get an argument going, you need some common ground with your intended audience. Ideally, you start with some shared common ground, and then maybe you also introduce factual considerations from science or elsewhere that you expect they will (or ought to) accept, and then you deliver the conclusion that moves them your direction. But on the question of animal consciousness specifically, people start so far apart that finding enough common ground to reach most of the intended audience becomes a substantial problem, maybe even an insurmountable problem.
The question “are garden snails phenomenally conscious?” or equivalently “is there something it’s like to be a garden snail?” admits of three possible answers: yes, no, and denial that the question admits of a yes-or-no answer. All three answers have some antecedent plausibility, prior to the application of theories of consciousness. All three answers retain their plausibility also after the application of theories of consciousness. This is because theories of consciousness, when applied to such a different species, are inevitably questionbegging and rely partly on dubious extrapolation from the introspections and verbal reports of a single species.
Philosopher Eric Schwitzgebel argues that good philosophical arguments should be such that the target audience ought to be moved by the argument, but that such arguments are difficult to make regarding animal consciousness, since there is no common ground.
Cf. his paper Is There Something It’s Like to Be a Garden Snail?