Physical sufferings? One thing is certain, you know; I think this was in the system, in the nature, that it was invented as an indicator; because, for example, if the body was disorganised in some way or other and this caused no suffering at all, one would never look for a way to stop the disorganisation. One thinks of curing an illness only because one suffers. If it caused you no unpleasantness, you would never think of being cured of it. So, in the economy of Nature I think that the first purpose of physical suffering was to give you a warning.
Unfortunately, there is the vital which pokes its nose into the affair and takes a very perverse pleasure in increasing, twisting, sharpening the suffering. Now this deforms the whole system because instead of being an indicator, sometimes it becomes an occasion for enjoying the illness, for making oneself interesting, and also having the opportunity to pity oneself—all kinds of things which all come from the vital and are all detestable, one more than another. But originally I think that it was this: “Take care!” You see, it’s like a danger-signal: “Take care, there’s something out of order.”
Ref : Questions and Answers – 1954