To approach the stranger is to invite the unexpected, release a new force, let the genie out of the bottle. It is to start a new train of events that is beyond your control.
The ideal reasoner, he remarked, would, when he had once been shown a single fact in all its bearings, deduce from it not only all the chain of events which led up to it but also all the results which would follow from it.
The past,' he thought, 'is linked with the present by an unbroken chain of events flowing one out of another.' And it seemed to him that he had just seen both ends of that chain; that when he touched one end the other quivered.