Let’s get the number of elements out of the way. The answer is, “It depends.”
If you are talking to a physicist, he’ll tell you, “Well, I’m not sure, but somewhere upwards of three thousand.” He’s including all the stable and reasonably stable nuclides known to exist. If he includes short-lived resonance states, the number is potentially infinite.
Or, he might say, “Six,” referring to quarks.
If you are talking to a chemist, he’ll likely tell you, “Ninety-two.” Those are the chemical elements that exist in nature. We’ve also managed to create a few more, and if the predicted “island of stability” actually exists, there could be as many as one hundred twenty-six.
If you are talking to a Chinese philosopher, he’ll say, “Five.” Earth, wood, metal, water, and fire.
A Japanese philosopher will also say “Five,” but he means earth, water, wind, fire, and “void.”
A Wiccan philosopher will say “Five,” and means earth, water, air, fire, and spirit.
A Western Renaissance philosopher would say “Four.” These are earth, water, air, and fire.
A physical chemist will look at these philosophical elements and say, “Oh, you don’t mean elements, you mean states of matter!” These are the three classical solid, liquid, and gas phases, plus (perhaps) plasma, though true plasmas don’t exist at the low temperatures of ordinary flame (which is just ordinary, if hot, gas). But again it depends, because there are at least twenty distinct states of matter, including such bizarre states as superfluidity (at very low temperatures) or degenerate matter (in the cores of collapsed stars).
My Bardic studies revolve around the four elements of the Western alchemical tradition: Earth, Water, Air, and Fire.
Apart from all the various “qualities” that are ascribed to these elements, the path through them is interesting.
The early Christian Gnostics, for instance, began with Earth, the so-called “hylomorphic state,” into which all of us are naturally born. We are then reborn through three progressive baptisms, first by water, then by fire, and finally by air/spirit (pneuma).
The Wiccan casting of the circle runs in exactly the opposite direction: it begins with air, then proceeds through fire, water, and finally, earth.
I find this opposition fascinating. The Gnostics were trying to get away from the impurities and evil of the world, the flesh, and the devil. Their baptisms are progressively more rarified and end with pure spirit, the state of Gnosis which brings the individual into full alignment with God.
Wiccans and modern Druids, by contrast, are born into a time when most of us live in our heads to begin with, building abstract air-castles like a “career” or a “retirement plan,” in the cerebral Cartesian world of cogito (I think), ergo sum (therefore I am). The meditative progression takes us from the air realms of overmuch thought back to earth, grounding, the wisdom of our bodies.
Both directions are useful.
But I think my favorite of all is the Discordian practice of working with the cross-quarters: Dust, Hot Air, Steam, and Mud.
Hail be to Mud!