What does it mean to "let something happen on its own?" Let's get specific. In genetic programming, sample populations of randomly generated algorithms are randomly cross bred and selected for fitness. The selection function is something like "better/worse at balancing a pencil on its point." After numerous generations you end up with a program that is an unreadable mess but which is very good at balancing a pencil. Similar techniques have been used to create electronic circuits. Again you get a circuit that's "unreadable" but does the selected function very nicely. Are these algorithms and circuits designed? Were they "let happen on their own?"
I can design an object without having any intention of actually creating it, and it's still my design.
I don't think that's a direct answer to my question you excepted which is, in addition to the intention to create that object is it also necessary to exhibit a specification to convince me that it is designed?
The point you may have been addressing is a prior one in my post, namely suppose there is intent and specification. To say that some observed phenomenon is the result of that design (see, I'm accepting your terminology), doesn't there have to be causal connection from the design to the object? IOW if the object is created independently of the design, then it was not a result of that design.
First of all, in your examples the selection criteria were designed. In the natural world, the selection criteria are as "designed" as the natural world itself - that is to say, it's part of the background in which animate and inanimate, biotic and abiotic matter all exist. So above and beyond the design of those initial criteria, those circuits and programs are not designed unless there's further intervention by the designer in their development.
To say that some observed phenomenon is the result of that design (see, I'm accepting your terminology), doesn't there have to be causal connection from the design to the object? IOW if the object is created independently of the design, then it was not a result of that design.
Yes, that's all true. But don't fall into the "if p then q = if q then p" snare. The fact that there is a causal connection does not mean that the final product was, in every detail, designed by whoever came up with the initial outline.