I would define a hierarchy of reflex < habit < intuition < 'thinking'. Though they all reflect some neurological activity, the only explicitly verbal level is 'thinking', and the others can be conducted unconsciously.
Usually I equate thought and consciousness, but perhaps there is a useful distinction there?
In mammals sentience precedes consciousness precedes sapience. In machines the necessity of the linkage is not clear. We can imagine sapience without consciousness, at least, but consciousness without sentience seems more questionable.