Parsimony is also about limiting the number of assumptions. Assuming one designer rather than an unknown number is an additional assumption. Thus it is more parsimonious to leave the number of designers unspecified until the evidence is in.
Which means that the typical ID position of assuming a single designer without considering the evidence cannot be justified by parsimony.
And even if we assume that the evidence favoured a designer, some unknown number would still be more parsimonious than assuming 1. Where's the need for an answer that would justify that assumption ?
(Personally, I would argue that none would be a more parsimonious answer, since the existence of a designer would raise much the same questions as the claimed evidence of design in the universe, questions that seem to be only answered by more assumptions).
quote: Arguably, there is no immediate need for it beyond completing the objective of this thread. More long-term reasons would be to clarify the proper usage of parsimony and to prevent evolutionists from wasting time on invalid criticisms of ID.
I'd say that you were wrong on all three points. The point of this thread is why IDists insist on a single Designer - and we must remember that they use this Designer to account for both the Universe and earthly life. Clearly parsimony does not support that - the most that you have claimed is a weak preference for a single designer of our universe, not a refusal to even seriously consider alternatives. The criticism that IDists mean God is not invalid at all. It's clearly supported by the evidence.
quote: I think I agree. But, just to clarify, are you suggesting that, even if we have already assumed design, "no designers" is the most parsimonious answer as to the number of designers?
No, although it seems to me that often special pleading is used to avoid the implication of an infinite regress of designers. Which is hardly parsimonious.
quote: I think I've done a good job of showing that parsimony does, in fact, support this. I would like you to explain where my argument is wrong.
To justify insisting on a single designer you would have to show that parsimony favours assuming one designer over making no assumption about the number of designers. So where is the argument that established that.
I would add that the qualities expected for a designer of the universe and a designer for life on Earth seem sufficiently distinct that I really have to question why parsimony would prefer one entity over two. It seems to me that an entity that WOULD do both is rather less likely than two separate entities even before we consider the reasons for thinking that there are multiple designers for life on Earth.
quote: I'm not clear on what you mean here. Can an argument that appeals to parsimony ever conclude anything more than "a weak preference"? I wouldn't think so.
I certainly can think of cases where parsimony is stronger than it is in this case. For instance if you have two theories which adequately describe some aspect of reality, but one requires large numbers of ad hoc assumptions, parsimony could even be a compelling argument. But in this case, where it is simply choosing which unevidenced assumption to use as a default - when there is no good reason for choosing any of them, it is hard to imagine a weaker argument.
In fact parsimony makes a stronger case for NOT assuming any particular number of designers. And this is why parsimony is AGAINST the ID assumption of a single designer. If ID were a genuine scientific enterprise this assumption would not be made at this point.