http://www.accesstoinsight.org/tipitaka ... .than.html
Consciousness is the what. Although it is not one consciousness but rather one moment or event of consciousness conditions the next. However, consciousness is not self because it is impermanent and unsatisfactory. If consciousness were self then self would arise and pass away thousands of times a day.
EDIT: Craving is the sustenance for consciousness to continue and kamma provides the field or range of possibilities for consciousness to re-arise in some other realm. Not saying I believe all that just that if you read the suttas this is what they point to.
"I don't envision a single thing that, when developed & cultivated, leads to such great benefit as the mind. The mind, when developed & cultivated, leads to great benefit."
"I don't envision a single thing that, when undeveloped & uncultivated, brings about such suffering & stress as the mind. The mind, when undeveloped & uncultivated, brings about suffering & stress."