Early in 2013 Dan Dennett had an interview posted at John Brockman’s Edge site, The Normal Well-Tempered Mind. He opened by announcing that he’d made a mistake early in his career, that he opted a conception of the brain-as-computer that was too simple. He’s now trying to revamp his sense of what the computational brain is like. He said a bit about that in that interview, and a bit more in a presentation he gave later in the year: If brains are computers, what kind of computers are they? He made some remarks in that presentation that undermine his position on words as memes, though he doesn’t seem to realize that.
Here’s the abstract of that talk:
Our default concepts of what computers are (and hence what a brain would be if it was a computer) include many clearly inapplicable properties (e.g., powered by electricity, silicon-based, coded in binary), but other properties are no less optional, but not often recognized: Our familiar computers are composed of millions of basic elements that are almost perfectly alike – flipflops, registers, or-gates – and hyper-reliable. Control is accomplished by top-down signals that dictate what happens next. All subassemblies can be designed with the presupposition that they will get the energy they need when they need it (to each according to its need, from each according to its ability). None of these is plausibly mirrored in cerebral computers, which are composed of billions of elements (neurons, astrocytes, …) that are no-two-alike, engaged in semi-autonomous, potentially anarchic or even subversive projects, and hence controllable only by something akin to bargaining and political coalition-forming. A computer composed of such enterprising elements must have an architecture quite unlike the architectures that have so far been devised for AI, which are too orderly, too bureaucratic, too efficient.
While there’s nothing in that abstract that seems to undercut his position on memes, and he affirmed that position toward the end of the talk, we need to look at some of the details.
The Material Mind is a Living Thing
The details concern Terrence Deacon’s recent book, Incomplete Nature: How Mind Emerged from Matter (2013). Rather than quote from Dennett’s remarks in the talk, I’ll quote from his review, “Aching Voids and Making Voids” (The Quarterly Review of Biology, Vol. 88, No. 4, December 2013, pp. 321-324). The following passage may be a bit cryptic, but short of reading the relevant chapters in Deacon’s book (which I’ve not done) and providing summaries, there’s not much I can do, though Dennett says a bit more both in his review and in the video.
Here’s the passage:
But if we are going to have a proper account of information that matters, which has a role to play in getting work done at every level, we cannot just discard the sender and receiver, two homunculi whose agreement on the code defines what is to count as information for some purpose. Something has to play the roles of these missing signal-choosers and signal-interpreters. Many—myself included—have insisted that computers themselves can serve as adequate stand-ins. Just as a vending machine can fill in for a sales clerk in many simplified environments, so a computer can fill in for a general purpose message-interpreter. But one of the shortcomings of this computational perspective, according to Deacon, is that by divorcing information processing from thermodynamics, we restrict our theories to basically parasitical systems, artifacts that depend on a user for their energy, for their structure maintenance, for their interpretation, and for their raison d’être.
In the case of words the signal choosers and interpreters are human beings and the problem is precisely that they have to agree on “what is to count as information for some purpose.” By talking of words as memes, and of memes as agents, Dennett sweeps that problem under the conceptual rug. Continue reading