One reason that the Toyota Production System is so effective is that it is built around many fundamental principles which apply universally. One of these pieces of timeless wisdom is that muri is bad and should be avoided. Muri is the “overburden” or “unreasonableness.” Many of us try to fit more into our lives or in our work than s reasonable. We try to overcome muri through heroic effort and work-arounds. Accepting muri as a condition of existence results in waste.
Two and a half centuries ago the philosopher Plato said:
If one sins against the laws of proportion and gives something too big to something too small to carry it – too big sails to too small a ship, too big meals to too small a body, too big powers to too small a soul – the result is bound to be a complete upset. In an outburst of hubris the overfed body will rush into sickness, while the jack-in-office will rush into the unrighteousness that hubris always breeds.
Much of what we do in Lean is to attempt to bring things back into balance with the laws of proportion. Supply and demand. Cycle time and takt time. Customers and suppliers. Workload and machine capacity. Work and life. Muri is at the root of waste, and there are many reasons we do muri.
In some cases muri is imposed upon, it is not a choice. If Plato is correct, some of us choose to do muri because of hubris. Hubris is excessive pride. It is a tragic flaw that results from a lack of balance in our understanding of ourselves. The opposite of hubris may be humility.
We should certainly challenge ourselves to do more than what we believe is possible, but not to deceive ourselves and go against the laws of proportion. That would be muri.