The term ‘weak teleology’ makes no sense to me. Either something has a natural purpose (or a designed purpose) or it doesn’t. If we say that rain is teleological we are simply claiming just one of the usefull purposes tthat rain serves. Surely it’s not possible for something to have multiple purposes. The first premise is not: We see that natural bodies work toward a few goals.
And the purpose of non living natural objects is simply the purpose that we nominate. Rain is useful in any number of ways but is there the one natural purpose that you can say it serves?
And as far as living organisms are concerned, evolution didn’t just blow Paley’s arguments out of the water, it also contradicts the idea of teleology in nature. The ‘purpose’ of an oak tree (and ‘purpose’ most definitely needs the scare quotes) is…to make another oak tree. And an acorn is part of that process. I don’t see anything deep and mysterious about it. I see no need for an ID’er to ensure the process continues in the right direction.
The arrow that was mentioned reaching it’s target assumes it was aimed for that specific point. But what those using it are metaphorically doing is following the flight of a randomly shot arrow and then running off to where it landed and drawing a bullseye around it.
So living objects do actually achieve their ‘goal’ by chance. Chance is a huge component of the evolutionary process (coupled with random selection to ensure an optimum outcome). But we can only nominate what that ‘goal’ actually is in retrospect.