Testing the Emergence Hypothesis

In considering the hypothesis of emergent phenomena there is, from a science perspective, a need and a responsibility to test the hypothesis, and so a singularly important question to be answered: what are the distinctive observable characteristics that an emergent phenomenon would display compared to one that is reductive. As I have already pointed out in this blog, there is a perfectly lovely historical example of such an approach in Einstein’s development of the Special Theory of Relativity. As Einstein exemplified in that case, it is one of the responsibilities of a scientist advancing a novel hypothesis to identify how it may be tested.

Now I suspect that some with a weaker grasp of the principles and practice of science would propose a straightforward test of demonstrating that an emergent principle correctly predicts a phenomenon where reductive principles were incapable of making the prediction. But I think most practicing scientists would recognize that this is not a sufficient test of the emergence hypothesis. Reductive principles may still correctly characterize a complex phenomenon in spite of the fact that we do not have the capability to apply them to predict it. Let’s take an extreme case to make the point: our capability to “predict” phenomena with quantum field theory is based on an infinite perturbation expansion – that is, everything, literally everything you can actually “predict” with it, is intrinsically an approximation; and yet no emergence proponents, not a one, has ventured to claim that the magnetic dipole moment of the electron is an emergent phenomenon even though we know we do not have the capability to predict it exactly. (Some folks just seem to go all wobbly over agreement to one part in ten billion.) So, let’s recap: even if a hypothesized emergent principle correctly predicted a phenomenon that reductive principles couldn’t because of our capability to apply them, this is not, I repeat not, a sufficient test of the emergence hypothesis.

Because of the capability dilemma, we are forced to apply a weaker and admittedly much less satisfying test of reductive principles for complex phenomena: examining whether the phenomena are consistent with the reductive principles, that is, examining a complex phenomenon looking for evidence that it violates the reductive principles. (Giraffe composed of atoms from the periodic table of the elements – check. Giraffe accelerates at 9.8 m/s^2 when dropped – check. Giraffe increases overall entropy of the universe when converting energy from one form to another – check. Etc., etc., etc.) Of every test of this kind of which I am aware (save one) there has never been a single instance that provided even the remotest evidence of violation of reductive principles. (The one instance that I am genuinely puzzled by is “dark energy”, which, oddly, seems to draw little attention from emergence proponents. That dark energy is some creepy weird shit, man!) And so here is the kicker for the emergence proponents: If a phenomenon is correctly described by an emergence hypothesis and yet the phenomenon is still consistent with reductive principles, then Occam’s Razor strongly suggests, if not demands, that the emergence hypothesis be considered unnecessary.

So, a challenge to emergence proponents: clearly and unequivocally identify the distinctive observable characteristics that an emergent phenomenon would display compared to one that is reductive and in a way that satisfies Occam. If you cannot or will not do this then it suggests that you are not doing science.

Update: OK, for the purpose of the challenge, let’s say reductive phenomena are those that are solely the consequence of the standard model of particle physics + the general theory of relativity + any as yet undiscovered components of the universe consistent with these [Higgs boson, dark matter (? – see NPR 13.7 Blog post @Mgleiser: Dark Matter), dark energy(?!?)] + any underlying reductive structure that subsumes these. Yuk. Not so pretty. But that’s still part of the problem: a claim of emergence could appear to offer clarity simply in contrast to murkiness in parts of our reductive understanding.

I know someone is going to call foul on this because we don’t know what the undiscovered components are and what the underlying reductive structure is. But turnabout is fair play: it’s just as much of a foul for emergence proponents to exclude these, because there are a number of very strong indicators that they are there. Without a knowledge of the undiscovered components and understanding of the underlying reductive structure a claim that a phenomenon is emergent cannot genuinely be tested against a competing reductionist claim, and as I have argued, if a phenomenon can be understood in terms of both an emergent hypothesis and a reductive hypothesis, Occam’s razor says reductive wins.

The posts on the NPR 13.7 blog suggest a range of interpretations of what constitutes emergence. For the purpose of the challenge, let’s say emergence is behavior which is demonstrably not solely a consequence of reductive phenomena as defined above.

Update: I hadn't noticed before I wrote this, but in the comments to one of the NPR 13.7 blog posts (see @SAK42: Breaking the Galilean Spell), there is indeed some heady discussion of a possible (extraordinarily speculative)relationship between dark energy and emergence. Like I said, that dark energy ...