As my reply to your original comment indicates I give them plenty of credit -- I'm not sure they didn't guess that cold was the absence of heat.

You have the pre-socratics a bit mixed up. Heracletus and Thales are before the five element system of Aristotle. Heracletus only had three elements in his cosmology and fire was the most important. Some ancient cosmologies made one element central...I'm not sure what that has to do with the question?

But certainly it is possible some of them surmised that cold was the absence of fire or something like that.