How is 'consciousness' (vinyaana) defined in Buddhist texts? How similar or different is it from the way the word is used these days -- particularly in scientific studies of consciousness ?
'It cognizes, it cognizes': Thus, friend, it is said to be 'consciousness.' And what does it cognize? It cognizes 'pleasant.' It cognizes 'painful.' It cognizes 'neither painful nor pleasant.' 'It cognizes, it cognizes': Thus it is said to be 'consciousness.' - MN 43
And what, bhikkhus, is consciousness? There are these six classes of consciousness: eye-consciousness, ear-consciousness, nose-consciousness, tongue-consciousness, body-consciousness, mind-consciousness. This is called consciousness. - SN 12.2
The six classes of consciousness should be understood. ’ So it was said. And with reference to what was this said? Dependent on the eye and forms, eye-consciousness arises; dependent on the ear and sounds, ear-consciousness arises; dependent on the nose and odours, nose-consciousness arises; dependent on the tongue and flavours, tongue-consciousness arises; dependent on the body and tangibles, body-consciousness arises; dependent on the mind and mind-objects, mind-consciousness arises. - MN 148