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听说股市大跌,很有趣的事儿——我不玩儿也不懂,在我眼里,那不过是一个涨落的时间序列。在非线性动力系统中,涨落可以“没有理由”地发生,跌呀涨呀,都是自然的。“没有理由”等于很多理由但不知道确定的理由。多个理由纠结起来,就“莫须有”了。如果硬要什么理由,还是一只看不见的手,但那手不是市场,而是自然。
七年前出现过类似的事情(报纸说it has been seven years since the darkest days of the recession),这正好响应了所谓的Joseph效应——据旧约故事(Gen.41),法老梦见河里走来七只肥美的母牛,却被七只干瘪的母牛吃了……Joseph解释说,梦境的意思是七年丰收后会闹七年的饥荒(Behold, therecome seven years of great plenty throughout all the land of Egypt: And thereshall arise after them seven years of famine)。
1968年,“分形之父”Mandelbrot用Noah效应——源于Genesisi 6:were all the fountains of the great deep broken up, and the windowsof heaven were opened. And the rain was upon the earth forty days and fortynights.——和Joseph效应来描述降雨极端降雨可以任意极端,而极端事件的持续时间也可以地长(extreme precipitationcan be very extreme indeed and long period of high or low precipitation can beextremely long)。为“混沌”立传的科学作家James Gleick说得更普适:
The"Noah" and "Joseph" Effects push in different directions, but they add up to this: trends innature are real, but they can vanish as quickly as they come. Thus, we canexpect what's been happening to continue to happen, but we should also expectthe unexpected.
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