Tuesday, March 18, 2008

On Emergent Causation

Max Ernst - "L'invention" or "L'oiseau de L'infini"


I recently read a one-page book review of a text whose subject matter strides through consciousness, free will, and emergence1. The review, by Todd S. Ganson, focuses on how the book, Did My Neurons Make Me Do it?, contends with a classic problem in neuroscience and the philosophy of mind: how is it possible to attribute mental states exclusively to the brain while avoiding a completely determined (lacking in free will) existence2?

Ever since Descarte pointed out the problems with dualism (a separation of the material and the mental), philosophers have been hard at work to find a middle ground between eliminating the mental and resorting to the supernatural. On the one hand, subjective conscious experiences cannot be denied, and it thus seems foolish to claim that they do not exist. However, there is absolutely no hint of a description as to how mentality might be caused by our biological apparatus, and it is thus somewhat attractive to assert some other author to our cognitive being, leading some to invoke the supernatural.

It has been suggested that one way to illustrate the manufacture of subjective experience is describe it as emergent. An example of an emergent property that I find to be particularly useful is the liquidity of water. A single molecule of H2O is not a fluid; rather the quality of being liquid is predicated on the interactions between many molecules. It is a property that emerges from the collective. Another example might be sand dunes: the patterns present in large quantities of grains are a feature of their concert, not guaranteed by the individuals.

Emergence has been very helpful to some because it paints a picture in which consciousness is not a priori predictable from the actions of single neurons, and yet retains a tangible quality. It doesn’t explain how the cerebrum causes consciousness but it does assert a mode in which consciousness might stymie our current scientific attempts to understand it based on the actions of single brain cells.

This book takes the utility of emergence one step further by putting forth the idea that emergence might help us reconcile our personal feeling of responsibility for our actions with our materially deterministic substrates of brain. The idea is that the complex system that is our emergent consciousness "can causally influence what bottom-level events occur by shaping the conditions that trigger these events.2"

An apt analogy here again is the sand dune. Its over-all shape determines how the individual grains interact with such forces as the wind. If it forms a flatter dune, it will be less susceptible to the whims of the wind while a tall structure will be more fragile. In this sense, the collective behavior can influence the actions of the individuals which make up the whole.

As mentioned previously, an alternative to searching for ways in which our seemingly ephemeral consciousness can effect the matter in our heads, we can adopt the view that free-will is an illusion; another mechanism of our brains that keeps us happy in the delusion that we're in charge of our own actions.

In any case, the suggestion concerning emergent causation may not explain anything in specific, but it does help to frame an alternative way to think about the relationship between that vexing triad I mentioned at the top, free will, consciousness and emergence.

Notes:

1. The interested reader might click here for RadioLab's excellent show on the subject of emergence.
2. Ganson, T.S. (2008) Finding Freedom Through Complexity. Science; 319:104

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