We don't need to end the series. Nothing compels us to do so. I subscribe to a Logical Positivistic interpretation of science, whereby a statement is not scientific unless it can be proved or disproved via observation; and truth is this Empiricist a posteriori knowledge, together with any analytic truths (propositions that is true by definition).
So, nothing demands it, except my faith in a logical framework for the universe, which behooves me to apply Occham's razor to all such teleological propositions: why have a Watchmaker's antecedent?, which is logically more complex to an equivalent extention of the universe back endlessly or as as an endless series.
So, you pluck your duck and I'll pluck mine. :D
I doubt the human race will ever answer this question. I don't think that our minds are built to comprehend this kind of knowledge.
<{POST_SNAPBACK}>
I would have thought someone so bold on the field of battle would not display such a lack of valour in the field of ontology. "