正如我的一个科学家朋友所说：如果你在一条山路上开车，驶向一处悬崖，而汽车的制动系统可能有问题，又正逢山雾弥漫，你应该开得更谨慎还是更随意呢？
As one scientist friend puts it: if you are driving on a mountain road, approaching a cliff, in a car whose brakes may fail, and a fog bank rolls in, should you drive more or less cautiously?