Not "all kinds of problems" but very specific kinds of problems which is possible to formalize into a math language. How would you go about inventing thermodynamics if you didn't know words "temperature" and "pressure"? You'd need to start for your senses that can tell you "this is a hot surface", or "this is a cold one", or "this one is colder than that", you need to decide that "coldness" is a "negative heat" (it is not the most obvious idea for an animal, because animals have as receptors for a cold, so receptors for a heat, you could feel hot and cold at the same time, if you managed to stimulate both kinds of receptors at the same time). Then you need to notice that some materials change volume when heated, then you need to come up with an idea to use measurements of a volume to measure a temperature, and only then you can try to invent pV=nRT, which becomes almost tautological at that point, because your operational definition of a temperature makes it equivalent to a volume.

After that you really can use calculus and make all sorts of quantitative statements about thermodynamic systems. But before all that "mere talk" was finished thermodynamics was not a kind of a problem calculus can deal with.