Consequently, changing them is not easy. Some humans believe that God invented the seven-day week and that it should not be tampered with for that reason. On the other hand, valid research about numerous past societies of the world challenges that view. There is a clear record in the long history of humans that depicts the use of weeks made up of three, four, five, six, and ten days - all operating quite successfully for their supporters. A broad generalization about these past experiences suggests that human beings have a deep need for periodic routines in their lives that are smaller than years or months but longer than single days.
Weeks respond to that desire.
We are so accustomed to the seven day week that we seldom give any attention to other possibilities. In fact, the records of the past strongly suggest that the number of days in the week have usually been controlled by two aspects of life on earth - the influence of religious beliefs and the leverage of the market place in human affairs. In the early years of civilization, both hunters and farmers found it a necessity to come together periodically to exchange their goods, and meeting that need in their lives created the week. The religious element in bringing about the concept of the week is more complex, and I hesitate to comment on it lest a viewpoint of mine annoy a reader of this document. Even a whisper about changing the seven day week raises the hackles of Christians, Jews and others.