Consciousness - on/off switch or spectrum?
On/off is indeed not the commonest view of consciousness. In Hindu philosophical circles, consciousness is thought of as continuous across living systems.  Humans have 'budding'consciousness, (plus free will), animals 'shuttered' and plants 'covered'consciousness, and these are points along a continuum.  (Reference example:  Hinduism and Science, by T D Singh; a paper in “Science and Religion: Global Perspectives”, June 4-8, 2005, in Philadelphia, PA, USA, a program of the Metanexus Institute).