The phrase "ascertaining which" is correct and usable in written English.
It can be used when you want to determine or find out specific information or details about something.
Example: "The committee is focused on ascertaining which candidates are best suited for the position."
Alternatives: "determining which" or "finding out which".
The trick is ascertaining which of these millions of variations divide us from them.
If, instead of expending effort ascertaining which veg might cure cancer, scientists could only make them taste like chocolate ice cream, the government's five-a-day campaign would be rendered obsolete.
Judge Whitman Knapp declared in a 1986 ruling in one of Mr. Giuliani's cases: "It may well be that the attorney general of the United States would be interested in ascertaining which of his employees was engaged in violating one or more of the statutes he or she was sworn to uphold".
It is an example of a "non-constructive" existence proof: demonstrating that one or another alternative must hold without providing a means for ascertaining which one does hold.
Another theme that emerges from the above is that of culpability, specifically, ascertaining which 'human' (e.g. captain or port operator) is the 'factor' to help in reducing risk.
Thus the semantic realist is prepared to assert that (G) is determinately either true or false, regardless of the fact that we have no guaranteed method of ascertaining which.
A very friendly chap was trying to ascertain which covers we had purchased.
Griffith-Jones concluded that nobody should be prosecuted, as it was impossible to ascertain which guards had inflicted which blows.
But when dealing with an individual it is important to ascertain which term they prefer, and to stick with it.
In the end, though, it was difficult to ascertain which players might have elevated their stock.
The results could help ascertain which features of this "zoo of possibilities" are more common and which are more rare, and how many solutions really are too many.
