common sense is over rated.
yes you are right. it is a catch 22. that is where the fire starts. lol. the importance on this is that the temp delta will be approaching zero. what you would be calculating is as the temp changes the resistance goes up and as the resistance goes up the temp change. at some point hopefully the temp change will be close to zero and then the resistance will stablize. What you don't want to see is the the temp change never gets to zero before the flash point of the material.