David Chalmers discusses the meaning of consciousness, remarking that we spent more time trying to decide if something is conscious or what parts of the brain it exists in, than even figuring out what really consciousness on an abtract level.
I agree with Chalmer’s conclusion that consciousness is the capacity to process information; increasingly complex systems (with more constituent pieces) are able to process more information, and thus display higher levels of consciousness.
Self-consciousness is, as anyone who is familiar with systems and biology knows, an emergent quality of neural systems. This “understanding” of the self within reality’s context is shared by all life, just extending to different levels of complexity. Awareness of the self as seperate system within the world around it is a characteristic shared, at least on a basal level, by essentially all animals within “craniata” (so possessing a skull, a more complex neural network, and myelin; the group is a division of the chordates). Higher level self-awareness, or having an abstract self-concept, extends to an understanding of the self, and others, in the context of reality, fantasy, AND perception.
These perceptual layers differ depending on the number of neurons and available dimensions of information processing (e.g sight, smell, sound) . Humans posses an especially large neo-cortex (the newest brain region), which allows humans to learn and create connections more dynamically and unlocks the potential to process novel abstract information (and make abstract decisions).
Our ability to integrate visual (or auditory) symbols with abstract ideas, and string it together into new connections which then indirectly affect our behavior, is an emergent quality of the millions of brain cells we have dedicated to dynamic use in the neocortex, and also a trade-off in neuron characteristics which likely led to the human abilities of writing, abstract reflection, and the concept of personal identity.
What does that mean? All life is self-conscious, even if it does not possess the abstract processing capacity necessary for “understanding” itself or others as concepts, or beyond the moment. We can make different judgements based on relative levels of different types of consciousness, such as what we have already done with existing laws about ethics in science or pet ownership. Whereas a bacteria, bug, or a planarian (which can actually turn into 2 individuals if cut in half) does not face any ethical review in their use in experiments, the use of mammals faces far more scrutiny and review.
Acknowledging that all life is conscious lets us more effectively reflect about our relationships to nature. I would argue that our ability to understand, to analyse data and draw conclusions, and to plan on an abstract level, gives us a certain responsibility within the world. We are part of a much larger system; 4th level consumers who have the most to lose by our active, continued, sustained, and extreme reduction of complexity in the biosphere (to put that in plainer terms: we are fueling an extinction rate approximately 1000x the background rate according to a meta-analysis published in the journal Science).
Consciousness, and self-awareness, are funny things. They make your interaction with the world more dynamic, even more open to different outcomes and possibilities than the molecules you are made of. The fact that we can interpret value, think abstractly, and plan strategically, gives us a wonderful gift to help encourage and sustain life on this planet. Should we really let that go to waste, and risk our own extinction through a failure to be conscious of an abstract emergency?