Do we know of any connections between the four noble truths and the four elements? or between the Buddha's teachings and alchemy?
Alchemy and the four elements are often perceived by modernists as the superstitions of the ancients. The Buddha is often described as an empiricist who emphasized "seeing" and who embodied the spirit of the modern scientific approach to inquiry and knowledge. Viewing the Buddha's teachings as "esoteric" becomes less common.
In the suttas, the four elements is used as attributes or qualities. For example, the earth element is associated with solidity which forms the basis for sensation, and makes the dissolution of the body a manifestation of aging sickness and death. The flowing quality of water makes attachments obstacles to a more natural flow which is associated with feelings of stress. Self view being as a strong intuition is associated with the fire element, and makes the fire sermon worthy of being the first Buddhist exposition of the teachings, where nibbana becomes well-designated as "coolness". The fourth element, which begins with right view and right thought makes the air element associated with the mind. Alchemy as an ancient way of thought have always been interested in transformation, and enlightenment seems to be a radical transformation in the ways we perceive, feel and think.
I would end this by quoting DN11:
It might be worth noting that the order/sequence of the four elements changed (except for fire/dhamma and air/mind) from earth, water, fire and wind to water, earth, fire, & wind."'Your question should not be phrased in this way: Where do these four great elements — the earth property, the liquid property, the fire property, and the wind property — cease without remainder? Instead, it should be phrased like this:
Where do water, earth, fire, & wind
have no footing?
Where are long & short,
coarse & fine,
fair & foul,
name & form
brought to an end?
"'And the answer to that is:
Consciousness without feature,[1]
without end,
luminous all around:
Here water, earth, fire, & wind
have no footing.
Here long & short
coarse & fine
fair & foul
name & form
are all brought to an end.
With the cessation of [the activity of] consciousness
each is here brought to an end.'"