[harperlee]

> The point, and the lesson I take from Cantwell Smith’s book, is that we can navigate these contradictions because we understand that our ideas are imperfect.

> One of the reasons Cantwell Smith believes that our oversimplified assumptions about ontology can explain the failure of the symbolic logic employed by what’s sometimes called Good Old-Fashioned AI, or GOFAI, is that more recent, and more successful, approaches to AI don’t depend on this kind of symbolic reasoning.

This puts forth a false dichotomy. The fact that classical first order logic assumes the rules are perfect does not invalidate all symbolic approaches. There are several types of modal logic that can be used to manage the idea of imperfect rules and imperfect, or subjective, knowledge about the world, even before starting with fuzzy or probabilistic logic.

In general, everything that can be talked about by humans, in principle, should be considered at the reach of symbolic approaches. That’s tautological, I know, but people seemingly have difficulties seeing the forest for the trees, as they restrict their mental model of symbolic logic to a 70s brand of prolog / Horn clause based predicate logic.

[smikhanov]

    > everything that can be talked about by humans, in principle, should be considered
    > at the reach of symbolic approaches

This doesn’t seem obvious to me — do you have any references that support this idea?

[harperlee]

Ok, to me it is obvious because words are themselves symbols - and thus everything that we can describe, and reason about, is symbolic. Us discussing here is symbolic, and a book is a complex, structured, symbolic message. Even if my understanding and your understanding of a particular word may differ somewhat, and there is subjective subsymbolic meaning (e.g. when I read “love”, I tie it with my life experience, and yours is nothing alike), when you compose complex messages those nuances lose importance.

If you read War and Peace, and I read War and Peace, even if our experience of the reading might be slightly different, it will be due to how we react to it, and to which passages we tend more attention; and we will generally agree on what Tolstoy wanted to communicate - not only on the words themselves, but on the world constructed, and the implications of it that are not explicitly described.

Another way to look at it: we don’t have any evidence that we need more than a symbolic approach to replicate what we do with language: and we have built a whole civilization based on written education, which is based in symbols.

[kordlessagain]

I would add that the non-language mental (visual) model each of us builds (in mind) of the world, in this moment, is both similar and different from other's models.

War and Peace is like a textual Xray of Tolstoy's brain, some of it being descriptive of what he saw while writing it. If our models are similar enough, together we'll see the same things he saw while we read it.

[PeterisP]

That is an interesting approach, but it also suggests that the (many!) important tasks and skills which we can do but can't easily describe and reason about (for example, image recognition, and why exactly a human would decide that this image is X but not Y; or how to ride a bicycle without falling down) likely shouldn't be solved by symbolic logic.

[harperlee]

I agree wholeheartedly about symbolism not being the only ingredient!

I have not read Marcus’s book and I don’t follow him a lot, but I think that they are also advocating a mixed approach.

[harperlee]

So perhaps I focused a little bit too much on model communication ability in the last comment, and not so much in intelligence.

To me, if you can operate on a model that you use to understand a bit of the world, serialize it into communication, and make it so that the other understands it, that evidences intelligence, but I agree that it is not a demonstration.

[smikhanov]

No, the word is not a symbol; the pair (word, its interpretation) can plausibly be considered as one.