Artificial Intelligence, Philosophy, Philosophy of mind, Wittgenstein

Reading Notes I: Tegmark and substrate independence


Tegmark (2017:67) writes “This substrate independence of computation implies that AI is possible: intelligence doesn’t require flesh, blood or carbon atoms.”. How should we read this? The background is that he argues that computation is independent of what we use for hardware and software and what is required is only that the matter we compute in fulfills som very simple conditions like sufficient stability (what would intelligence look like if it was based on gases rather than more solid matter, one could ask – remembering the gas giants in Bank’s novels, by the way – sufficiently large gases may be stable enough to support computation?). But what is more interesting here is the quick transition from computation to intelligence. Tegmark does not violate any of his own assumptions here – he is exceptionally clear about what he thinks intelligence is and builds on a Simonesque notion of attaining goals – but there still seems to be a lot of questions that could be asked about the move from computation to intelligence. The questions that this raises for me are the following: 

(i) Is computation the same as intelligence (i.e. is intelligence a kind of computation – and if it is not what is it then?)

(ii) It is true that computation is substrate agnostic, but is not substrate independent. Without any substrate there can be no computing at all, so what does this substrate dependence mean for intelligence? Is it not possible that the nature of the matter used for computation matters for the resultant computation? A very simple example seems to be the idea of computation at different temperatures and what extreme temperatures may lead to (but maybe Tegmark here would argue that this violates the stability condition). 

(iii) In a way this seems to be assuming what is to be proven. What Chalmers and others argue is that while computation may be substrate agnostic, cognition or consciousness is not. If there was a way to show that intelligence is substrate specific – only certain classes of matter can be intelligent – what would that look like? 

(iv) The question of consciousness is deftly avoided in the quoted sentence, but is there an aspect of observation, consciousness and matter somewhere that seems to matter. I know too little about the role of observation in quantum physics to really nail this down right now, but is it not possible that there exists certain kinds of matter that can observe, and others that cannot? 

(v) Even if intelligence is substrate agnostic, as computation, may it not be dependent on certain levels of complexity in the organization of the computation and may it not be the case that these levels of complexity can only be achieved in certain classes of matter? That is, is there an additional criterion for intelligence, in addition to the stability criterion laid out by Tegmark, that needs to be taken into account here? 

(vi) What would the world have to be like for intelligence NOT to be substrate agnostic? What would we call the quality that some classes of matter has that others lack and that means that those classes can carry intelligence. 

(vii) the close connection between computation and intelligence seems to open itself up to a criticism based on Wittgenstein’s notion of an “attitude to a soul”. Is this just a trite linguistic gripe, or a real concern when we speak about intelligence? 

(viii) It seems as if we can detect computation in matter, does this mean that we can detect intelligence just by detecting computation? Clearly not. What is it that we detect when we detect intelligence? This brings us back to the question of tests, of the Turing test et cetera. The Turing test has arguably been passed many times, but is not an interesting test at all – but is there a test for intelligence that can be reduced to a physical measurement? There certainly should be a test for computation that can be easily designed, right? 

(ix) Intelligence is a concept that applies to action over a longer time than computation. Does the time factor change the possible equivalence between the concepts? 

A lot to think about. Fascinating book so far. 

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