well it's no use speculating on what someone else meant, but the expirations are part of the incentive: it's not that if you figure out a new configuration, you

well it's no use speculating on what someone else meant, but the expirations are part of the incentive: it's not that if you figure out a new configuration, you get it FOREVER. You get it for twenty years. So it's a limited reward - just enough to motivate you. It goes right along with Congress's constitutional mandate: >To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries. Although this perhaps confuses things by mixing copyright into it. By the way I think in this day and age, patents should be for 5-7 years. Not twenty and certainly not longer. innovation has sped up. but anyway the whole idea is that to promote the progress of useful arts - so the incentive has to be just big enough to cause that promotion...