Bechukosai

The valuation of a male shall be: for someone twenty years of age to sixty years, the valuation shall be fifty silver shekels, of the holy shekel (Vayikra 27:3)

We may ask, why did the Torah set the valuation of a man at the precise value of fifty coins? Perhaps we may answer by combining the following three ideas.

The first idea comes from the commentary of the Rav on a Mishna in mesechat ahalos (2:5). The Rav there asks why is it that the minimum amount of human flesh needed to convey tumah is set at precisely the volume of an olive? Likewise why is the minimum amount of blood needed to convey tumah set precisely at the volume of a reviyus? The Rav answers that this amount of flesh and this amount of blood is what a human being possesses in its mother's womb when it first develops into a living creature. Since this measurement is the smallest size of flesh and blood needed to bring about new life it also attains importance for the rules of contamination that occur when life is no more.

The second point comes from tosofos in Shabos. Tosofos there writes that the measurement of an olive amount of flesh is the same as a measurement of a reviyus volume of blood. This is so because when blood congeals it shrinks to the size of an olive.

The third point comes from a tosofos in sotah (5). Tosofos there writes that the weight of a reviyos of human blood is exactly twenty-five coins.

If we take all these three ideas together we can derive as follows: Since the weight a reviyus of blood is exactly twenty five coins and the amount of an olive of flesh is the same as a measurement of blood, then together they weigh exactly fifty coins. Furthermore, since the bare minimum of life is an olive of flesh and a reviyus of blood, which weigh fifty coins as explained, this then can serve as the value of man in his prime from twenty to sixty. When man is in his youth or in his advanced years his value will be adjusted from this amount.