Daniel Dennett - Real Patterns (1991)

Dennett elegantly bridges the chasm between cellular automata and human social intentionality by leveraging the concept of a stable pattern and its status of reality within the world. "Real Patterns" a great piece of work, and its logic is worth following closely.

The presentation of a "pattern" is done by recourse to information theory and Chaitin's compressibility of a data stream. Though it's not explicitly mentioned, there's also an assumption of what Shannon and Weaver would term a "sender", encoding some structure based on an underlying pattern (through which the output is compressed - using, say, the shared grammar of a chess game). The receiver then interprets this data, perceiving the pattern through its underlying actuality. Chess pieces placed randomly would, to a professional, be significantly harder to perceive and recall; to a non-player, however, both layouts would appear arbitrary, and no pattern could be perceived.

Thus, patterns are real yet potentially only discernible from a given perspective. Dennett asserts that a pattern exists in some data "if there is a description of the data that is more efficient than the bit map, whether or not anyone can concoct it". We can infer from this, then, that there are relative magnitudes of pattern-ness, correlating with the degree of information compressibility that we can apply.

When we apply our formidable pattern-matching apparatus in the real world, we form what Sellars terms a "manifest image", overlaid onto our sensations through acquired knowledge and folk psychology, which allows us to make judgements as to what is presented to us and so make intentional decisions. This is done through a significantly statistical, inductive process: a highly weighted network of probabilities based on accumulated experience.

Now, back to the Game of Life. Dennett's critical move here is to go beyond glider guns and explain how we can create a Turing-complete machine from aggregates of Life cells, essentially constructing three new levels in the Life hierarchy

• at L=0, individual cells
• at L=1, persistent aggregates of gliders, blinkers, beehives, etc
• at L=2, aggregates of L=1 units which can perform logical operations
• at L=3, aggregates of logic structures capable of playing a (deterministic or pseudo-random) game of chess

The thought experiments that we are left to take away include: what is the ontological status of the patterns (glider guns, logic gates, etc) that have been created through these illusory collections of cells? At what perspectives would we be able to perceive our Life chess-player as such, and at what perspectives would it appear to be a random, chaotic mulch? Does the latter matter?

A really beautiful work, and one which subtly begins to also emphasise the statistical nature of how such patterns (on a vastly complex scale) may function in consciousness and other real-world emergent scenario. Just as Bedau argued previously, what arises are whole classes of macro phenomena which can be grouped by some mean tendencies: the tendency for 2-2 Life to result in a chaotic slime, the tendency of birds to flock in synchrony, the tendency of a human agent to act in loosely predictable, intentional ways. The metaphysical reality of an abstract centrepoint to such tendencies is difficult to confirm, but the broader reality of such persistent, useful patterns is difficult to deny.

This marks the end of the "Philosophical Perspectives on Emergence" section. Next up: Scientific Perspectives.

Brian McLaughlin - Emergence and Supervenience (1997)

Read as PDF

In terms of its subject matter, McLaughlin's second paper in the collection follows on chronologically from his first. In the wake of quantum mechanics and other modern scientific advances, he affirms that: "On the current evidence, it appears that all fundamental forces are exerted below the level of the atom". So, is it still logically tenable to appeal to truly "emergent" forces which are genuinely radically unexplainably from underlying processes?

Yes, is the result, though it's highly unclear that there actually exist any such forces. In brief, McLaughlin completes the hard work of the later Emergentists by formulating a rigorous definition of what it would mean to be truly, intuitively emergent:

If P is a property of w, then P is emergent if and only if (1) P supervenes with nomological necessity, but not with logical necessity, on properties the parts of w have taken separately or in other combinations; and (2) some of the supervenience principles linking properties of the parts of w with w's having P are fundamental laws.

Got that?

The magic lies in the use of "nomological necessity", which approximates to a semantic relationship of implication (if "the parts have property A" is true, then "the whole has property B" is true) rather than necessity through logical deduction (such as that of "all bachelors are male"); and the "fundamental laws" clause, which are akin to the Emergentist "configurational laws": that is, non-deducible first principles.

This definition is constructed through the use of the supervenience relation (see left), which sees wide use throughout analytic philosophy. To say that mental states supervene on neural states is to say that any change in mental state also entails (or, alternatively considered, requires) a change in neural state. Conversely, many neural states (labelled A on diagram) may potentially map to the same mental state (B).

So, there we go. Through this modal-logic scaffolding, emergence has been shown to be logically valid. However, McLaughlin himself is the first to admit that, even so, the only remaining known candidate for true emergence is consciousness - and this too is only left as an "open question". The resolution will come if it is ever revealed that the principles on which conscious states supervene are "fundamental" (i.e., in accordance with vitalism) or otherwise. My feeling is the latter.