The limit of our mechanistic thinking is that we never find ourselves at time zero. We observe the consequences of our interventions on a system whose various pathologies may have been developing long before we came on the scene. If we fail to remember this simple fact, we are biased into thinking that all of our observations are direct effects of our actions. Instead, we should remember that we are stepping into an ever moving stream whose source we cannot see. Likewise, we are unlikely to ever see its full downstream course. The best we can hope for is to look far enough up- and down-river to accurately place ourselves in the rush and to understand the transience of our presence and interventions.