If you went back to, I would guess, 1946, and worked to prevent your parents’ marriage in 1947, you would still have existed in that year; you would not go out of existence just because you had influenced events. The same would apply even if you had only been in 1946 one microsecond before shooting the man who would otherwise have become your father.

In the case of a missing man, you were not required to search for him just because a record somewhere said you had done so. But how else would you stand a chance of finding him? You might possibly go back and thereby change events so that you did find him after all—in which case the report you filed would “always” have recorded your success, and you alone would know the “former” truth.

The Mediterranean floor lay ten thousand feet below sea level. The inflow took most of that drop within a fifty-mile strait. Its volume amounted to ten thousand cubic miles a year, a hundred Victoria Falls or a thousand Niagaras.