Linas, Mike and Jim

I find this to be a most-interesting conversation. Primarily, because it 
suggests that the development of AGI may not only be challenged by the 
development of competent theory, but also by programming capabilities to put 
the theory into practice.

Evolving such an architecture then, should desired outcomes be for an AGI 
entity to achieve self-theory and self-programming? In its most-simplistic 
from, a symbol is but a suitable abstraction of a greater reality, similarly to 
how a symbol of a red-heart might be an abstraction of a sentient being. 
Concept? Context? Meaning? Transaction.

Who, or what decides what the symbolic world should look like and its 
meaningfulness? The global state of social evolution may cause terrible 
confusion in any learning entity. The learning objectives should be specific, 
not generalized. Isn't learning incorrectly worse than not learning at all?

I think, there should be a general agi-architecture, replete with the capacity 
to develop and function within a generic world view. Furthermore, I think the 
real value would be derived from specialized AGI. Maybe beyond that, an AGI 
architecture would - in future - morph via its own social networking and 
inherent capabilities to become more than the sum of its parts.

To do so, would take a lot more than intersections. I agree with the statements 
made about binary/vector theory, but it seems obvious to me that this would not 
be sufficient for this task. You implied fractals. To my mind, that would be 
the only way to proceed. As such, I think the primary issue remains a design 
issue.

Robert Benjamin

________________________________
From: Linas Vepstas <[email protected]>
Sent: Monday, 18 February 2019 10:36 PM
To: AGI
Subject: Re: [agi] Some thoughts about Symbols and Symbol Nets



On Mon, Feb 18, 2019 at 1:17 PM Mike Archbold 
<[email protected]<mailto:[email protected]>> wrote:
I'm not sure I completely follow your point, but I sort of get it.

I tend to think of symbols as one type of the "AI stuff" a computer
uses to think with -- the other main type of "AI stuff" being neural
networks. These have analogies to the "mind stuff" we use to think
with.

Symbol systems and neural-net systems can be seen to be variants of the same 
thing; two sides of the same coin. I posted an earlier thread on this. There's 
a 50-page long PDF with math, here: 
https://github.com/opencog/opencog/raw/master/opencog/nlp/learn/learn-lang-diary/skippy.pdf

roughly: both form networks. They differ primarily in how they represent the 
networks, and how they assign weights to network connections (and how they 
update weights on network connections).

On their own, symbols don't mean anything, of course, and inherently
don't contain "understanding" in any definition of understanding.

Is there a broad theory of symbols? We kind of proceed with loose
definitions. I remember reading the Newell and Simon works, and they
say AI strictly in terms of symbols and LISP (as I recall anyway).

Yes. The "broad theory of symbols" is called "model theory" by mathematicians. 
It's highly technical and arcane. It's most prominent distinguishing feature as 
that everything is binary:  it is or it ain't. Something is true, or false.  A 
formula takes values, or there is no such formula. A relation binds two things 
together, or there is no relation.  There's no blurry middle-ground.

So, conventionally, networks of symbols, and the relations between them, and 
the formulas transforming them -- these form a network, a graph, and everything 
on that network/graph is a zero or a one -- an edge exists between two nodes, 
or it doesn't.

The obvious generalization is to make these fractional, to assign weights. 
Neural nets do this. But neural nets do something else, that they probably 
should not: they jam everything into vectors (or tensors) This is kind-of OK, 
because the algebra of a graph is a lot like the algebra of a vector space, and 
the confusion between the two is an excusable mistake: it takes some 
sophistication to realize that they are only similar, but not the same.

I claim: fix both these things, and you've got a winner.  Use symbolic systems, 
but use fractional values, not 0/1 relations.  Find a good way of updating the 
weights. So, deep-learning is a very effective weight-update algorithm. But 
there are other ways of updating weights too (that are probably just as good or 
better.  Next, clarify the vector-space-vs-graph-algebra issue, and then you 
can clearly articulate how to update weights on symbolic systems, as well.

(Quickly explained: probabilities are not rotationally-symmetric under the 
rotation group SO(N) whereas most neural-net vectors are: this is the spot 
where deep-learning "gets it wrong": it incorrectly mixes gibbs training 
functions with rotational symmetry.)

So Jim is right: discarding symbolic systems in favor of neural nets is a 
mistake; the path forward is at the intersection of the two: a net of symbols, 
a net with weights, a net with gradient-descent properties, a net with 
probabilities and probability update formulas.

-- Linas


On 2/18/19, Jim Bromer <[email protected]<mailto:[email protected]>> wrote:
> Since I realized that the discrete vs weighted arguments are passe I
> decided that thinking about symbol nets might be a better direction for me,
>
> 1. A symbol may be an abstracted 'image' of a (relatively) lower level
> object or system.
>   An image may consist of a feature of the referent, it may be an icon of
> the referent or it may be a compressed form of the referent.
> 2. A symbol may be more like a 'label' for some object or system.
> 3. A generalization may be represented as an image of what is being
> generalized but it also may be more of a label.
> 4. An 'image', as I am using the term, may be derived from a part or
> feature of an object or from a part of a system but it may be used to refer
> to the object or system.
> 5. An image or label may be used to represent a greater system. A system
> may take on different appearances from different vantage points, and
> analogously, some features of interest may be relevant in one context but
> not from another context. A symbol may be correlated with some other
> 'object' and may stand as a referent to it in some contexts.
>
> So, while some symbols may be applied to or projected onto a 'lower' corpus
> of data, others would need to use an image to project onto the data field.
> I use the term, 'lower' somewhat ambiguously, because I think it is useful
> to symbolize a system of symbols so a 'higher' abstraction of a system
> might also be used at the same level. And it seems that a label would have
> to be associated with some images if it was to be projected against the
> data.
>
> One other thing. This idea of projecting a symbol image onto some data, in
> order to compare the image with some features of the data, seems like it
> has fallen out of favor with the advancements of dlnns and other kinds of
> neural nets. Projection seems like such a fundamental process that I cannot
> see why it should be discarded just because it would be relatively slow
> when used with symbol nets. And, there are exceptions, GPUs, for example,
> love projecting one image onto another.
> Jim Bromer


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