Pellatarrum: Elemental Energies

Back when I first started talking about Pellatarrum and the elemental seasons, people were mystified as to why I placed earth opposite fire instead of the more traditional water.

My initial explanation was along the lines of "Sleep outside at night without a ground cloth. The earth will suck the warmth from you. Ergo, earth is cold, the opposite of heat." People didn't completely buy that explanation, though, because both wind and water can pull the heat from you.

I think my original explanation failed because it was rooted in trying to explain Pellatarran metaphysics from inside the universe instead of outside. Therefore I will explain it using game mechanics.

Each elemental state/plane is associated with a form of energy in Pathfinder: fire is fire (duh), water is cold, air is lightning and earth is acid for some damn reason. Now fire and air are fine and sensible, and while I can see water being cold, I just cannot see earth being acid. Why is the "liquid" energy not associated with the only elemental liquid? Water erodes solids; acids and bases corrode solids. There's a similarity there. Conversely, water can be hot: just look at hot springs and steam and humid days.

Then I had an interesting thought: if I make acid the water energy and cold the earth energy, then there's an interesting balancing act going on with the elemental planes. Fire, the element of change and heat, is opposed by earth, the element of cold and stasis; air and water, the two fluids, then balance each other out. This gives us a really interesting set of poles (heat/cold, change/stasis) separated by a yin-yang pairing of opposite sides of the same coin -- air and water can be both clear or opaque; they are seen yet unseen (you see fog but do not see air; you see water but also see through it); and they exist within the other (bubbles of air within water and rain falling through the sky).

I found this really compelling and poetic, and yet nontraditional, which is an excellent summation of how Pellatarrum ought to work.

So that's why in my game setting, earth is the element of cold and water is the element of acid.