Jochen’s paper Von Neumann Minds: Intentional Automata has been published in Mind and Matter.
Intentionality is meaningfulness, the quality of being directed at something, aboutness. It is in my view one of the main problems of consciousness, up there with the Hard Problem but quite distinct from it; but it is often under-rated or misunderstood. I think this is largely because our mental life is so suffused with intentionality that we find it hard to see the wood for the trees; certainly I have read more than one discussion by very clever people who seemed to me to lose their way half-way through without noticing and end up talking about much simpler issues.
That is not a problem with Jochen’s paper which is admirably clear. He focuses on the question of how to ground intentionality and in particular how to do so without falling foul of an infinite regress or the dreaded homunculus problem. There are many ways to approach intentionality and Jochen briefly mentions and rejects a few (basing it in phenomenal experience or in something like Gricean implicature, for example) before introducing his own preferred framework, which is to root meaning in action: the meaning of a symbol is, or is to be found in, the action it evokes. I think this is a good approach; it interprets intentionality as a matter of input/output relations, which is clarifying and also has the mixed blessing of exposing the problems in their worst and most intractable form. For me it recalls the approach taken by Quine to the translation problem – he of course ended up concluding that assigning certain meanings to unknown words was impossible because of radical under-determination; there are always more possible alternative meanings which cannot be eliminated by any logical procedure. Under-determination is a problem for many theories of intentionality and Jochen’s is not immune, but his aim is narrower.
The real target of the paper is the danger of infinite regress. Intentionality comes in two forms, derived on the one hand and original or intrinsic on the other. Books, words, pictures and so on have derived intentionality; they mean something because the author or the audience interprets them as having meaning. This kind of intentionality is relatively easy to deal with, but the problem is that it appears to defer the real mystery to the intrinsic intentionality in the mind of the person doing the interpreting. The clear danger is that we then go on to defer the intentionality to an homunculus, a ‘little man’ in the brain who again is the source of the intrinsic intentionality.
Jochen quotes the arguments of Searle and others who suggest that computational theories of the mind fail because the meaning and even the existence of a computation is a matter of interpretation and hence without the magic input of intrinsic intentionality from the interpreter fails through radical under-determination. Jochen dramatises the point using an extension of Searle’s Chinese Room thought experiment in which it seems the man inside the room can really learn Chinese – but only because he has become in effect the required homunculus.
Now we come to the really clever and original part of the paper; Jochen draws an analogy with the problem of how things reproduce themselves. To do so it seems they must already have a complete model of themselves inside themselves… and so the problem of regress begins. It would be OK if the organism could scan itself, but a proof by Svozil seems to rule that out because of problems with self-reference. Jochen turns to the solution proposed by the great John Von Neumann (a man who might be regarded as the inventor of the digital computer if Turing had never lived). Von Neumann’s solution is expressed in terms of a tw0-dimensional cellular automaton (very simplistically, a pattern on a grid that evolves over time according to certain rules – Conway’s Game of Life surely provides the best-known examples). By separating the functions of copying and interpretation, and distinguishing active and passive states Von Neumann managed to get round Svozil successfully.
Now by importing this distinction between active and passive into the question of intentionality, Jochen suggests we can escape the regress. If symbols play either an active or a passive role (in effect, as semantics or as syntax) we can have a kind of automaton which, in a clear sense, gives its own symbols their interpretation, and so escapes the regress.
This is an ingenious move. It is not a complete solution to the problem of intentionality (I think the under-determination monster is still roaming around out here), but it is a novel and very promising solution to the regress. More than that, it offers a new perspective which may well offer further insights when fully absorbed; I certainly haven’t managed to think through what the wider implications might be, but if a process so central to meaningful thought truly works in this unexpected dual way it seems there are bound to be some. For that reason, I hope the paper gets wide attention from people whose brains are better at this sort of thing than mine…