Samizdat

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Tag: Lincos

Eco: Artificial Intelligence

The Arecibo Message.svg

Frank Drake (1930-), Carl Sagan (1934-96), et al, The Arecibo Message, 1974. The Arecibo Message was broadcast into space via FM radio waves from the Arecibo radio telescope in Puerto Rico on 16 November, 1974. Aimed at the globular star cluster M13, the message comprised 1,679 binary digits. Total broadcast time was less than three minutes in duration. This representation of the message is by Arne Nordmann, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. 

Lincos does furnish us with an image of a language that is almost purely “mental” (its level of expression is supported by nothing more than electromagnetic phenomena). This reminds us of other languages which are, in one way or another, the heirs of the ancient search for the perfect language.

Computer languages, like BASIC or Pascal, are, in fact, a priori languages. They are not full languages because their syntax, though rigorous, is simplified and limited, and they remain parasitic on the natural languages which attach meanings to their empty symbols, which, for the most part, serve as logical connectors of the type if . . . then.

None the less, they are universal systems: they are comprehensible to speakers of differing natural languages and are perfect in the sense that they permit neither error nor ambiguity.

They are a priori, in that they are based not on the rules which govern the surface structures of natural languages, but rather, ideally, on a presumed deep grammar common to all natural languages.

They are, finally, philosophical because they presume that this deep grammar, based on the laws of logic, is the grammar of thought of human beings and machines alike. They also exhibit the two limitations inherent in philosophical a priori languages:

(1) their rules of inference are drawn from the western logical tradition, and this may mean, as many have argued, that they reflect little more than the basic grammatical structures common to the Indo-European family of languages;

(2) their effability (sic) is limited; that is, they are capable of expressing only a small proportion of what any natural language can express.

The dream of a perfect language which covers all the meanings and connotations of the vocabulary of a natural language, and in which human beings and machines can engage in “meaningful” conversations (or machines can draw inferences as happens in natural languages), underlies much of contemporary research into artificial intelligence.

Machines are provided, for example, with rules of inference by which they can “judge” whether or not a certain story is coherent, or decide that, if someone is ill, then someone needs medical assistance–and so on.

By now, the literature on this subject is vast, and the proposed systems are many: they run from those that still adhere to the ideal of a componential semantics based on primitives, to those that furnish the machine with schemes of action or a typology of “frames,” “scripts” and “goals.”

In general all of these projects succeed in solving certain problems only through imposing ad hoc solutions, which work only for local portions of the range of action of natural languages.”

Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 310-2.

Eco: Space Languages

hansfreudenthal

Hans Freudenthal (1905-1990). This photograph is assumed to be copyrighted and unlicensed, but qualifies as fair use under United States copyright law to illustrate the subject in question where no free equivalent is available, as Professor Freudenthal is deceased and no free replacement can be made. 

“Almost at the bounds of science fiction, though still with an undoubted scientific interest, is the project of the Dutch mathematician Hans A. Freudenthal (Lincos, 1960) for a language in which eventual encounters with the inhabitants of other galaxies may be conducted (see Bassi 1992).

Lincos is not designed as a language to be spoken; it is rather a model for inventing a language and at the same time teaching it to alien beings that have presumably traditions and biological structure different from ours.

Freudenthal starts off by supposing that we can beam into space signals, which we might picture as radio waves of varying length and duration. The significance of these waves derives not from their expression-substance, but rather from their expression-form and content-form.

By endeavoring to understand the logic that determines the expression-form being transmitted to them, the space aliens are supposed to extrapolate a content-form that will not be alien to them.

During the first phase, the messages consist of regular sequences of pulses. These are intended to be interpreted quantitatively–four pulses standing for the number 4, etc. As soon as it is assumed that the aliens have correctly interpreted these first signals, the transmission passes to the second phase, in which it introduces simple arithmetic operators:

* * * < * * * *

* * * * = * * * *

* * * * + * * = * * * * * *

In the next phase, the aliens are taught to substitute for the pulses a system of binary numbers (in which * * * * = 100, * * * * * = 101, * * * * * * = 110); this makes it possible, using only ostension and repetition, to communicate some of the principle operations in mathematics.

The transmission of temporal concepts presents a more complex problem. Freudenthal, however, presumes that by constantly receiving a signal of the same duration, constantly associated to the same number of pulses, the aliens will begin to compute a certain duration in seconds. Lincos also teaches conversational rules, training the aliens to understand sequences such as “Ha says to Hb: what is that x such that 2x = 5?”

In one sense, we are treating the space aliens like circus animals; we subject them to a repeated stimulus, giving them positive reinforcement whenever they exhibit the desired response. In the case of animals, however, the reinforcement is immediate–we give them food; in the case of aliens, the reinforcement cannot but be a broadcast signal that they should interpret as “OK.”

By this means, the aliens are meant to learn to recognize not only mathematical operations but also concepts such as “because,” “as,” “if,” “to know,” “to want,” and even “to play.”

The project presupposes that the alines have the technological capability to receive and decode wave-length signals, and that they follow logical and mathematical criteria akin to our own.

They should share with us not only the elementary principles of identity and non-contradiction, but also the habit of inferring a constant rule through induction from many similar cases.

Lincos can only be taught to those who, having guessed that for the mysterious sender 2 x 2 = 4, will assume that this rule will remain constant in the future. This is, in fact, a big assumption; there is no way of ruling out that there exist alien cultures who “think” according to rules which vary according to time and circumstances.

What Freudenthal is aiming for is, explicitly, a true characteristica universalis; in Lincos, however, only a handful of original syntactic rules are formulated in the beginning. As to the rest (as to, for example, the rules governing questions and answers), the model implicitly assumes that the interlocutors will use the rules, and even the pragmatics, of a natural language.

We can, for example, imagine a community of angels, each of whom either reads the thoughts of the others or learns truths directly through beholding them in the mind of God: for such beings, the set of interactional rules governing questions and answers would make no sense at all.

The problem with Lincos is that, although provided with a formal structure, it is conceived as an instrument for “natural” communication, and thus it is inherently uncertain and imprecise. In other words, it cannot possess the tautological structure of a formalized language.

Lincos is probably more interesting from a pedagogical point of view: can one teach a language without ostension?

If the answer is positive, Lincos would allow a situation different from that imagined by philosophers of language, when they skeptically imagine a scene in which a European explorer interacts with a native, each party tries to communicate with the other by pointing at bits of space-time and uttering a given sound, and there is no way for the explorer to be certain whether the native is denoting a given object located in that space-time portion, or the fact that something is happening there, or is expressing his or her refusal to answer (see Quine 1960).”

Umberto Eco, The Search for the Perfect Language, translated by James Fentress, Blackwell. Oxford, 1995, pp. 308-10.

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