Furthermore, could our experience of our selves as a single, unitary consciousness be just an illusion?
By mere existence I mean it could consist of only experiencing a signal sensory input, even if that input is forgotten forever after processing and responding to it. So I am using the broad definition of consciousness, it is not necessary to be able to reflect on one's experience, only to be having it in order to be conscious.
People tend to assume there are things which even though they receive inputs that they then react to are not conscious, even in this sense. But what is materially different about our own material structure and how we process information that would justify such a position?
Could it not be that all things that receive inputs and produce outputs in the Universe experience a form of consciousness? That consciousness is found in the smallest of particles, as for something not to take inputs and produce outputs would effectively render it non-existent for all practical purposes?
But aren't we different? Not in any way science can show, or if it can I haven't come across it and would like to see it. That we sometimes act according to things we've learned in the past wouldn't count, because even if you act according to things you learned in the past that's still responding to inputs, ones that the brain put into storage (memory) to be used later. Same for genetic information, that would likewise be another input.
And then think about the subconscious, and how some people experience multiple personality disorder and the distinct possibility that our experience of a unitary consciousness is just an illusion created by the interaction of the neurons (which we have no good reason to determine as nonconscious as they also act on inputs and outputs), and furthermore the interaction of the molecules in the neurons, primarily the DNA contained in the nucleus, and further down the interaction of individual atoms, and finally particles. More interactions are of course involved. Dark matter passes through the human body, as does radiation of various sorts, though our structure may work in a way that prevents their influence on our illusionary "unitary consciousness" or not, science still has some work to do to determine the role of dark matter in the Universe.
EDIT: Shoot, I forgot to fix this. I had meant to put "The Mere Existence of..." in the title, which would explain the line "by the mere existence of..."
But anyways that's what I'm going for, not the definition of consciousness, I'm asking what physical properties are responsible for it and I've already defined it for the purposes of the question: Merely being able to experience things, even if unremembered and even if it's the most simple, meaningless form of "experiencing things" possible.