Thursday, October 26, 2017

Searle almost blows it on computational intelligence, almost, but not quite [biology]

John Searle has long been a critic of the pretensions of artificial intelligence to, well, you know, intelligence. He’s perhaps best know for his Chinese room argument. To parody:
Some guy’s in a room. Knows English well but doesn’t speak a lick of Mandarin. But he’s got a flotilla of yellow pads on which there’s a blizzard of instructions in English and pseudo-code for writing Mandarin. A Chinese speaker slips some statement in Mandarin through a slot in the wall. The guy goes to work with his yellow pads and blue pencils and, in due course, scribbles some Mandarin on a slip of paper and sends it back out through the slot. And thus begins a convincing ‘conversation’ in Mandarin. But, really, our guy doesn’t know a jot of Mandarin.
In Searle’s terms what our guy is doing is all syntax, no semantics. And that’s what computers do, all syntax, but not a hint of semantics.

I wasn’t convinced back then – a lot of people weren’t – and I retain that old skepticism, though there are days when I think the argument might have some merit, under a particular interpretation.

Anyhow, I just came across a 2014 article in The New York Review of Books in which Searle takes on two recent books:
Luciano Floridi, The 4th Revolution: How the Infosphere Is Reshaping Human Reality, Oxford University Press, 2014.

Nick Bostrom, Superintelligence: Paths, Dangers, Strategies, 
Oxford University Press, 2014.
Searle’s argument depends on understanding that both objectivity and subjectivity can be taken in ontological and epistemological senses. I’m not going to recount that part of the argument. If you’re curious what Searle’s up in this business to you can read his full argument and/or you can read the appendix to this post, where I’ve quoted a number of passages from a 1995 book in which Searle lays out matters with some care.

Searle sets up his argument by pointing out that, at the time Turing wrote his famous article, “Computing Machinery and Intelligence”, the term “computer” originally applied to people (generally women, BTW) who performed computations. The term was then transferred to the appropriate machines via the intermediary, “computing machinery”. Searle observes:
But it is important to see that in the literal, real, observer-independent sense in which humans compute, mechanical computers do not compute. They go through a set of transitions in electronic states that we can interpret computationally. The transitions in those electronic states are absolute or observer independent, but the computation is observer relative. The transitions in physical states are just electrical sequences unless some conscious agent can give them a computational interpretation.

This is an important point for understanding the significance of the computer revolution. When I, a human computer, add 2 + 2 to get 4, that computation is observer independent, intrinsic, original, and real. When my pocket calculator, a mechanical computer, does the same computation, the computation is observer relative, derivative, and dependent on human interpretation. There is no psychological reality at all to what is happening in the pocket calculator.
And that, believe it or not, is his argument. Oh he develops it, but really, that’s it, right there.

It seems rather like a semantic quibble that completely misses the substantive issue: can ‘intelligence’ and/or ‘consciousness’ be constructed from the kinds of circuits we use to build digital computers? Assume, for the sake of argument, that it can be done. Who the hell cares what we humans call it or attribute to it, the fact of the matter is that it’s now arguing the point with us. For all I know it might even argue that, no, it’s not intelligent; it’s all syntax, no semantics. Ain’t that a fine kettle of fish?

Return to Searle:
Except for the cases of computations carried out by conscious human beings, computation, as defined by Alan Turing and as implemented in actual pieces of machinery, is observer relative. The brute physical state transitions in a piece of electronic machinery are only computations relative to some actual or possible consciousness that can interpret the processes computationally.
See what I mean?

[And what if we choose to talk of computation in some sense other than that defined by Turing?]

Then, in his final section, Searle manages to pull a rabbit out of the hat:
Suppose we took seriously the project of creating an artificial brain that does what real human brains do. As far as I know, neither author, nor for that matter anyone in Artificial Intelligence, has ever taken this project seriously. How should we go about it? The absolutely first step is to get clear about the distinction between a simulation or model on the one hand, and a duplication of the causal mechanisms on the other. Consider an artificial heart as an example. Computer models were useful in constructing artificial hearts, but such a model is not an actual functioning causal mechanism. The actual artificial heart has to duplicate the causal powers of real hearts to pump blood. Both the real and artificial hearts are physical pumps, unlike the computer model or simulation.

Now exactly the same distinctions apply to the brain. An artificial brain has to literally create consciousness, unlike the computer model of the brain, which only creates a simulation. So an actual artificial brain, like the artificial heart, would have to duplicate and not just simulate the real causal powers of the original. In the case of the heart, we found that you do not need muscle tissue to duplicate the causal powers. We do not now know enough about the operation of the brain to know how much of the specific biochemistry is essential for duplicating the causal powers of the original. Perhaps we can make artificial brains using completely different physical substances as we did with the heart. The point, however, is that whatever the substance is, it has to duplicate and not just simulate, emulate, or model the real causal powers of the original organ. The organ, remember, is a biological mechanism like any other, and it functions on specific causal principles.
That, it seems to me is the question: How much of specifically human biochemistry is essential for duplicating the causal powers of the human brains? Perhaps the answer is zero, in which case so-called strong AI is in business and one day we’ll see computers whose psychological behavior is indistinguishable from that of humans and, who knows, perhaps superior. But if specifically human biochemistry is required, than artificial cleverness is all we’ll ever get, though some of that cleverness will, no doubt, be remarkable. As indeed, some of it already is.

But what does this stuff about biochemistry have to do with that earlier point about certain electronic machinery doing computing ONLY because we say that’s what it’s doing? In the machine there is some sequence of transitions between input to the machine and output from it. We say that’s computation. But really, it’s not. It’s just electrons buzzing about in circuits.


Searle on subjective and objective in ontological and epistemological senses

Some early passages from John R. Searle, The Construction of Social Reality, Penguin Books, 1995.

p. 1:
This book is about a problem that has puzzled me for a long time: there are portions of the real world, objective facts in the world, that are only facts by human agreement. In a sense there are things that exist only because we believe them to exist. I am thinking of things like money, property, governments, and marriages. Yet many facts regarding this things are ‘objective’ in the sense that they are not a matter of your or my preferences, evaluations, or moral attitudes.
p. 4:
...the complex structure of social reality is, so to speak, weightless and invisible. The child is brought up in a culture where he or she simply takes social reality for granted. We learn to perceive and use cars, bathtubs, houses, money, restaurants, and schools without being aware that they have a special ontology. They seem natural to us as stones and water and trees. Indeed, if anything, in most cases it is harder to see objects as just natural phenomena, stripped of their functional roles, than it is to see our surroundings in terms of their socially defined function.
p. 5:
The invisibility of the structure of social reality also creates a problem for the analyst. We cannot just describe how it seems to us from an internal “phenomenological” point of view, because money, property, marriages, lawyers, and bathtubs do not seem to have a complex structure. They just are what they are, or so it seems. Nor can we describe them from the external behaviorist point of view, because the description of the overt behavior of people dealing with money, property, etc., misses the underlying structures that make the behavior possible. Nor, in turn, can we describe those structures as sets of unconscious computational rules, as is done by contemporary cognitive science and linguistics , because it is incoherent to postulate an unconscious following of rules that is inaccessible in principle to consciousness. And besides, computation is one of those observer-relative, functional phenomena we are seeking to explain.
p. 6:
The truth is, for us, most of our metaphysics is derived from physics (including the other natural sciences). Many features of the contemporary natural science conception of reality are still in dispute and still problematic. For example, one might think that the Big Bang Theory of the origin of the universe is by no means well substantiated. But two features of our conception of reality are not up for grabs. They are not, so to speak, optional for us as citizens of the late twentieth and early twenty-first century. It is a condition of your being an educated person in our era that you are apprised of these two theories: the atomic theory of matter and the evolutionary theory of biology.
p. 7:
Here, then, are the bare bones of our ontology: We live in a world made up entirely of physical particles in fields of force. Some of these are organized into systems. Some of these systems are living systems and some of these living systems have evolved consciousness. With consciousness comes intentionality, the capacity of the organism to represent objects and states of affairs in the world to itself. Now the question is, how can we account for the existence of social facts within that ontology?
pp. 7-8:
Much of our world view depends on our concept of objectivity and the contrast between the objective and the subjective. Famously , the distinction is a matter of degree, but it is less often remarked that both “objective” and “subjective” have several different senses. For our present discussion two senses are crucial, an epistemic sense of the objective-subjective distinction and an ontological sense. Epistemically speaking, “objective” and “subjective “ are primarily predicates of judgments. We often speak of judgments as being “subjective” when we mean that their truth or falsity cannot be settled “objectively,” because the truth or falsity is not a simple matter of fact but depends on certain attitudes, feelings , and points of view of the makers such subjective judgments with objective judgments, such as the judgment “Rembrandt lived in Amsterdam during the year 1632.” For such objective judgments, the facts in the world that make them true or false are independent of anybody’s attitudes or feelings about them. In this epistemic sense we can speak not only of objective judgments but of objective facts. Corresponding to objectively true judgments there are objective facts. It should be obvious from these examples that the contrast between epistemic objectivity and epistemic subjectivity is a matter of degree.

In addition to the epistemic sense of the objective-subjective distinction, there is also a related ontological sense. In the ontological sense, “objective” and “subjective” are predicates of entities and types of entities, and they ascribe modes of existence. In the ontological sense, pains are subjective entities, because their mode of existence depends on being felt by subjects. But mountains , for example, in contrast to pains, are ontologically objective because their mode of existence is independent of any perceiver or any mental state.
Continuing directly on from the previous, p. 8-9:
We can see the distinction between the distinctions clearly if we reflect on the fact that we can make epistemically subjective statements about entities that are ontologically objective, and similarly, we can make epistemically objective statements about entities that are ontologically subjective. For example, the statement “Mt. Everest is more beautiful than Mt. Whitney” is about ontologically objective entities, but makes a subjective judgment about them. On the other hand, the statement “I now have a pain in my lower back” reports an epistemically objective fact in the sense that it is made true by the existence of an actual fact that is not dependent on any stance, attitudes, or opinions of observers. However, the phenomenon itself, the actual pain, has a subjective mode of existence.

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