> I think that by an analogy I can give some idea of the difficulty, in this way. I do not know if you have ever had the experience - I have - of sitting on the beach with several towels, and suddenly a tremendous downpour comes. You pick up the towels as quickly as you can, and run into the bathhouse. Then you start to dry yourself, and you find that this towel is a little wet, but it is drier than you are. You keep drying with this one until you find it is too wet - it is wetting you as much as drying you - and you try another one; and pretty soon you discover a horrible thing - that all the towels are damp and so are you. There is no way to get any drier, even though you have many towels, because there is no difference in some sense between the wetness of the towels and the wetness of yourself. I could invent a kind of quantity which I could call 'ease of removing water'. The towel has the same ease of removing water from it as you have, so when you touch yourself with the towel, as much water comes off the towel on to you as comes from you to the towel. It does not mean there is the same amount of water in the towel as there is on you - a big towel will have more water in it than a little towel - but they have the same dampness. When things get to the same dampness then there is nothing you can do any longer.

... and then he continue to explain how this is related to temperature and entropy.

The whole book is worth reading.