Again a treatise by Plutarch online at LacusCurtius: this time, the venerable author deals with the Principle of Cold (Περὶ τοῦ πρώτως Ψυχροῦ), and that turns out to be far more interesting than you would think.
First, Plutarch argues that an “element of cold” exists, and then, he Plutarch considers what that element may be. Since fire is obviously excluded, can it be air, as the Stoics believe, or water, as Empedocles holds? Or, indeed, may it be earth itself? This latter opinion is put forward by Plutarch as his own contribution to theoretical physics, but the essay closes with a recommendation to skepticism. The Sage of Chaeronea may not have regarded his attempted proof as cogent, as indeed it is not.