To be fair, there's lots of other organs in your body that are already single points of failure. Regardless, there's probably a reason we evolved with two kidne

To be fair, there's lots of other organs in your body that are already single points of failure. Regardless, there's probably a reason we evolved with two kidneys. My personal theory (i.e. I have no idea if there's any actual research on this hypothesis) is that before humans discovered cooking, agriculture, sanitation, etc., there were a lot more diseases and toxins and such in the food we ate, so the organs responsible for handling them were much more active than they are now. This is why you can get rid of your tonsils, appendix, a large fraction of your liver, and one of your kidneys and still be "fine". (To reiterate, though, I don't know how much research there is to support this theory.)