One way of putting it is to say that even in the matter of mere operations-let alone the highest reaches of the spirit -we do nit have much hard date on the performance characteristics of the human system in our strange conditions.

• 不妨可以这样认为，仅就人的活动而言，我们至今也没有关于人类在陌生的环境中行为特征的过硬材料，就更不用说人类的最高精神境界了。