What are the parameters of kavod ha'brios?

Question

When I was younger I was told that in extenuating circumstances one can rip toilet paper on shabbos (preferably not on the perforations) due to kavod ha'brios. This concept is applied in other places such as the way we hang a corpse who has been killed by beis din. What are the halachik parameters for this concept and how far does it extend? For instance if the bathroom were dark could one turn on a light or light a candle (malacha m'deoraisa) because of kavod ha'brios? Can a person be m'vater on their kavod ha'brios (some extreme practices such as rolling in the snow naked come to mind)?

If you have the sources for the above cited halachos please post

Answer 1

The most significant restriction on K'vod HaBrios is that it only applies to rabbinical enactments. I have never seen anyone permit tearing toilet paper directly, but I have seen it permitted to do so in a "backhanded" manner because of k'vod habrios. This is an more contemporary example of a classic example of the leniency of k'vod habrios found in O.C.312:1. There we find permission to handle stones, which are otherwise muktzeh (a rabbinic prohibition) to clean oneself in the lavatory. The Gemara in Shabbos 81b says "גדול כבוד הבריות שדוחה את לו תאשה שבתורה. Great is the honor of a person, which pushes aside a "Torah" prohibition. While superficially it would appear from this that k'vod habrios would permit the transgression of a Torah commandment, the "Torah prohibition" the maxim refers to is the prohibition against deviating from the words of the Sages (though I do not have an explicit reference at the moment, but according to here we may expect to find it in Menachos 38)).