I think that you can grant that Emergent Phenomena exist and can be explained in principle from reductionist principles, but so what if in fact explain  in fact?
<p>I would claim that of Weak Emergence, it is more than convenience!
The difference between principle and practice is vital!
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Are the interaction rules between two electrons inherent in the electrons?
I claim that is a philosophical question and not a physics question.
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The strong emergence notion implies, perhaps, that a physicist may go into a lab in the future and discover a particle disobeying one of its ‘rules’ in order for some larger system to act in accordance with some “strong emergent phenomenon”.
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I suspect that our visual system’s built in edge detectors are constructed in part by genes that are peculiar to edge detection.
These genes work to modify the general mechanisms (genes) to build nerves.
If this is so we must consider this in connectionist designs.
It is yet problematic whether this situation should be viewed as abstraction by nature.
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Concepts are abstractions. A circle is an abstraction.
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Is <a hre=http://en.wikipedia.org/wiki/Exaptation>exaptation</a> an abstraction?
Most, perhaps all, cited examples of <a href=https://en.wikipedia.org/wiki/Exaptation>exaptation</a> seem short of abstraction.
Perhaps exaptation is a precursor of abstraction.