I've analogized it to worrying about whether the Vikings got here before Columbus, and if any other Europeans did it too, and if so, precisely what routes they took. Interesting to think about, but it doesn't matter, really. Columbus is the one who made all the difference.
There may be some overlap between the causative properties that form natural history and those that form human history.
The distinction between determinate and indeterminate events is no reason to hold that absence of knowledge about causative properties means that such properties are actually indeterminate. That is an epistemological mistake. Indeterminacy is either a postive or negative characteristic.