It’s a discrete phenomenon because my consciousness is not your consciousness. I do not have two consciousnesses at once. Each consciousness is separate from any others - hence, discrete.
As for how I know another person is conscious?
Consciousness is a documented phenomenon that has existed since before I existed. My lived experience matches documented evidence of consciousness, thus I can conclude that, by and large, humans are conscious, although I cannot determine directly whether or not another person is conscious without depending on their testament. They could be a philosophical zombie - a thing that has all outward behaviors of a conscious being without having a consciousness, including lying about having a conscious experience - but the likelihood is low.
It’s a discrete phenomenon because my consciousness is not your consciousness. I do not have two consciousnesses at once. Each consciousness is separate from any others - hence, discrete.
As for how I know another person is conscious?
Consciousness is a documented phenomenon that has existed since before I existed. My lived experience matches documented evidence of consciousness, thus I can conclude that, by and large, humans are conscious, although I cannot determine directly whether or not another person is conscious without depending on their testament. They could be a philosophical zombie - a thing that has all outward behaviors of a conscious being without having a consciousness, including lying about having a conscious experience - but the likelihood is low.