Within the Numbered Discourses 3.61. The Great Chapter, Sectarian Tenets, the Buddha states, ‘“These are the six elements”: this is the Dhamma I’ve taught …’ That’s what I said, but why did I say it?
There are these six elements: the elements of earth, water, fire, air, space, and consciousness.
I was unaware that consciousness was considered an element and would like to understand more. Does anyone have some good suggestions for further investigation?
MN 140 is also a good explanation that could serve you in CIPS and the OP:
After a series of “What is the earth, water, fire, air, space elements?” exposition, the Buddha goes on to Consciousness:
What remains is sheer consciousness, pure and bright. And what does that consciousness know? It cognizes ‘pleasure’ and ‘pain’ and ‘neutral’. Pleasant feeling arises dependent on a contact to be experienced as pleasant. When they feel a pleasant feeling, they know: ‘I feel a pleasant feeling.’ They know: ‘With the cessation of that contact to be experienced as pleasant, the corresponding pleasant feeling ceases and stops.’