A cornerstone of the theory of evolution are so-called “vestigial organs,” or body parts that have no function and exist in our bodies only because they are “left over” from some evolutionary ancestor. One classic example is the appendix at the end of the small intestine.

It takes no small amount of arrogance and foolishness to proclaim that any part of the body has no purpose, given the enormous complexity of the body as a whole, or even a single cell or protein for that matter. On the contrary, the more biologists study the body, the more amazed they become at the astounding order, the precision – that is to say, the wisdom – of every aspect of it. Is it somehow more rational to believe that all this arose by chance?

As science has advanced, more and more of those formerly “vestigial” organs have been crossed off the list, as it was learned that they actually serve an important function in the body. The appendix, for example, is actually a reservoir for “good bacteria,” or the normal flora of our digestive system. The human gut is host to trillions and trillions of friendly bacteria, which protect it from other bacteria that cause disease, and also aid in digestion. If these good bacteria are killed off by disease or infection, the reservoir in the appendix can help to repopulate them.

Another example of a “vestigial organ” is the human coccyx, or tailbone. Long believed to be an evolutionary leftover, it is actually an important bone for maintaining an upright posture while sitting, and is the anchor point for many of the muscles of the pelvis.

Another organ long dismissed is the fifth toe, which monkeys use to hold on to branches as they leap from tree to tree. Humans don’t use their feet for climbing, but the fifth toe helps us fine-tune the movements of our feet.

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In a similar vein, scientists used to consider faith to be a useless vestige of a past, unenlightened age. They believed that as our knowledge of the world grows, the less dependent we become on supernatural explanations.