Meaning and information

I don't remember meeting him, but, when I was a child, we often used to drive past a house belonging to my father's old colleague, 'Sticky' Glew. (My mother had been introduced to him, and had trouble deciding how to address him. She wisely opted for 'Mr Glew'.) It amused my father that his friend had written a dissertation on 'the meaning of meaning'.

"For thousands of years," writes Seth Lloyd (in his book, Programming the universe (Vintage, 2007)), "philosophers have tried to determine what 'meaning' means, with mixed success." (p. 24)

Lloyd's work (in quantum computing and quantum communication systems) is based around the technical concept of information. But strings of bits and so on mean nothing in themselves: they are meaningful only if they can be interpreted. "Meaning is defined only relative to a scheme of interpretation ..." (p. 25)

"Consider the string of bits ... : 1001001 1101110 0100000 1110100 1101000 1100101 0100000 1100010 1100101 1100111 1101001 1101110 1101110 1101001 1101110 1100111. Interpreted as a message encoded in ASCII, this string means 'In the beginning'. But taken on its own, with no specification of how it is to be interpreted, it means nothing other than itself." (p. 25) And, of course, 'In the beginning ...' is interpreted according to the conventions of the English language. As Lloyd points out, natural languages are rich in ambiguity, which is "a key aspect of poetry, fiction, flirting, and plain everyday conversation." (p. 27)

But sometimes, in order to understand basic concepts - like meaning - it is useful to strip away complexities and ambiguities and look at simple models, as Wittgenstein did in his account of language games. Imagine a simple language game in which a builder says "Block" and the assistant hands him a block, or "Slab" and the assistant hands him a slab. The meaning of each expression is to be found in the action the expression provokes.

Lloyd relates Wittgenstein's idea to computers and computing. "The meaning of a computer program written in a particular computer language," he writes, "is to be found in the actions the computer performs as it interprets that program. All the computer is doing is performing sequences of elementary logic operations, such as AND, NOT and COPY ... The computer program unambiguously instructs the computer to perform a particular sequence of those operations. The 'meaning' of a computer program is thus universal, in the sense that two computers following the same set of instructions will perform the same set of information-processing operations and obtain the same result." (p. 26-27)

Meaning, then, is interpreted information. We don't need a theory of meaning such as philosophers have attempted to build. Philosophy (most notably the philosophy of language and metaphysics) has drifted into unproductive areas reminiscent of scholasticism in which intellectual work is done without first ensuring that there is an important intellectual task to address.

Of course, the word 'meaning', like many English words, can be used in different ways, and a careful analysis of the context of use will reveal subtle - and not so subtle - differences. One sense of the word - rather different from most of the others is 'general significance' or 'point' or 'purpose', as in the sentence, 'My life seems to lack meaning.' I have not been talking here of this generalized kind of meaning, but of the ordinary - and primary - uses of the word in relation to information and communication. And, understood as interpreted information, it seems to me a perfectly clear and unmysterious concept. Trying - as some philosophers do - to make a big issue of what they call 'aboutness' or 'intentionality' (which doesn't mean what non-philosophers think it means) constitutes unnecessary mystification.*

The remarkable advances in computing and information and communication technologies during the last 70 years have thrown up many real problems of a fundamental nature, but they require scientific knowledge (not just knowledge of formal logic and philosophy) to address. In particular, the parallels between thermodynamics and information theory are clearly rich in new problems which would benefit from informed reflection. For example, all matter and energy is subject to the laws of thermodynamics, but all matter and energy - everything there is - is also subject to the laws of information. Information theory appears to be a more fundamental and all-encompassing theory than thermodynamics (which can now be seen as just a special case of information theory).

Though I doubt the value of much recent philosophical work in the areas of language and meaning, some very important foundational work has certainly been done by philosophers, philosophically-inclined mathematicians and logicians. The key advances were made during the 19th and early 20th centuries. The work of George Boole, Giuseppe Peano, David Hilbert, Bertrand Russell, A.N. Whitehead and many others provided the conceptual tools which made the development of the electronic computer and sophisticated communication technologies possible. Claude Shannon's development of what he called a 'mathematical theory of communication' and which has come to be known as information theory was based largely on the work of George Boole.

Information has come to be seen as physical - it is no longer seen as abstract, disembodied and unquantifiable. It is always tied to a physical representation: a mark on paper, a charge, a spin, a sequence of bases in DNA. Information processing occurs not just in computers and brains but throughout the physical world.

In 1961 Rolf Landauer came up with a principle with (it is said) startling implications: that one essential information processing operation (erasure) cannot occur without causing heat to dissipate into the environment (thus increasing the entropy of the universe). The processing of information is a thermodynamic process (just as thermodynamic processes are informational) and erasure is an irreversible operation. Negation can be reversed by a second negation. Addition can be reversed by subtraction. But erasure cannot be undone.

I will resist the temptation to discuss the implications of Landauer's principle (which I believe are not good!). I am a layman in these matters, but the role that information processing seems to play in every aspect of nature intrigues me. I am trying at least to understand the fundamental principles, and to relate the sort of thing one learns within the context of philosophical logic - e.g. that there are any number of alternative systems of logic - to the apparently more constrained context of real-world information processing.


* Much philosophical work in recent decades in areas such as ethics, metaphysics, the philosophy of language and even logic has been done by people with a commitment to a religious view of the world (or at least with an anti-physicalist orientation), and has been motivated (I believe) by an attempt to undermine physicalism and to save a space for the spiritual (broadly interpreted). Such a motivation does not invalidate the work, but I personally don't think a convincing case against physicalism has been made.

The ground of being

For almost the whole of human history - until, say, the 19th century - the intellectually curious could expect their culture's deepest and most universal explanatory systems to be not only intellectually but also emotionally satisfying. Mythic, religious or metaphysical systems provided explanations (albeit inadequate as we now see) of both the natural and the social/moral world.

Our best theories of physics, by contrast, omit - as they must - all the things our complex brains seem primarily designed to deal with. And the men (and very few women) at the forefront of research in physics and related sciences often come across as lacking in social awareness.

Writing style (in non-technical contexts) gives a lot away about a person, and so often, when reading autobiographical or semi-autobiographical books by leading scientists, I find myself making allowances for what seems to be a certain childish quality, a lack of critical or social or psychological awareness or sophistication - even sometimes a certain moral immaturity and recklessness. It seems almost as though - as with autistic savants - these people's brains are not 'wasting' any time or energy on the immensely complex processing involved in being socially (and morally?) aware.

There are exceptions, of course. Seth Lloyd's book Programming the universe (Alfred A. Knopf, 2006) is not only beautifully written in a spare and restrained style, but it is also saying something of profound importance. Lloyd takes the tradition of digital physics associated with such names as Edward Fredkin and John Wheeler and updates it to encompass the concept - and the reality - of quantum computing.

Wheeler suggested that the bit (i.e. information) was the fundamental building block of reality rather than the physical particle; Lloyd and his colleagues deal not in bits but in qubits (quantum bits). The cosmos is not a classical computer but rather a quantum computer - computing itself. A more recent work by Vlatko Vedral, Decoding reality (OUP, 2010), makes similar claims.

According to this way of thinking, in order to understand any complex system the most important thing is to understand how information is represented and processed within that system. But underlying all systems are just a handful of simple logical operations. There is something very beautiful about this, and I am sometimes tempted to devote myself in a serious way to learning more about these fundamental processes - and even writing about them. But I'm not sure the payoff would be worth it. Fascinating as these ideas are in general terms, I fear that the deeper one goes, the less interesting they become - except in a technical sense. The puzzles of quantum computing are fascinating - but no more so than any other complex joint problem-solving exercise. The fascination is not the emotionally satisfying fascination associated with a global understanding of one's place in nature.

My provisional conclusion is that ultimately our ordinary lives are more complex and interesting than these fundamental processes. To imagine otherwise is to exhibit traces of theological thinking, the old sense that there is something very wonderful at the heart of reality - God, the Ground of Being. But it's looking increasingly likely that there's just a whole lot of computing going on, willy-nilly, and without a master programmer.

Rewriting history

Back in May I wrote a little piece called 'Out of my comfort zone' in which I touched on some ideas on the nature of the universe put forward by Seth Lloyd and - more recently - by Vlatko Vedral. Vedral's book, Decoding reality: the universe as a quantum computer (Oxford University Press) came out earlier this year.

In his review in New Scientist (there is a pay wall, so I can't give the link) Lloyd praises the book but also shows irritation that Vedral did not even mention Lloyd's book of several years ago on the same theme (Programming the universe). Lloyd also points out a mathematical howler which, as he saw it, was surprising in a leading researcher.

What jumped out at me in Vedral's book was an amazingly slipshod paragraph about Nietzsche which reflects badly both on the author and on Oxford University Press. It helps confirm my suspicion that books have become commodities - objects for sale - and the quality of the content is secondary. Scholarly values are out the window. (Vedral boasts of his 'streetwise' style; more worrying is the sense that he feels that historical truth doesn't matter.)

According to Vedral, Nietzsche " ... based the whole of his philosophy on the premise that physics implies that life is ultimately pointless, as eventually it must become extinct. The idea of absolute progress (the idea of progress to the point of perfection) must therefore ultimately be an illusion, in direct contrast to the ideas underpinning the evolution of life. Nietzsche thought that this conclusion is so difficult to live with that he needed to introduce the concept  of a 'superhuman' - an improved version of the human, able to come to terms with the fact that life cannot achieve absolute progress. Nietzsche, sadly, did not himself have the key attributes of his superhuman - he spent the last 11 years of his life in a lunatic asylum unable to deal with life, disillusioned and alone." (p.60)

Readers who know more about Nietzsche than I do can draw their own conclusions. I simply point out that the German thinker believed in an 'eternal return' - that life would ultimately repeat itself (in fact a scarier idea than extinction!). Also, he had an organic brain disease - he wasn't made insane by his philosophy; and he was looked after by his family after his breakdown, so did not spend the time in an asylum, and nor was he alone. He was so far gone after his breakdown that he could hardly be called 'disillusioned'.

These may be deemed unimportant errors, but they are symptomatic of an unfortunate attitude. It's a pity, because the book is worth reading. It is serving to crystallize some of my ideas, and I'll have more to say about it later.

Out of my comfort zone

Further to my recent post on intellectual curiosity... (This is where it takes me sometimes.)

There is a very commonly held view that each era's key technology tends to be incorporated into cosmological and other explanations (e.g. the mechanistic, 'clockwork' universe of the 17th and 18th centuries). Supposedly, we project our technology onto reality and mistake a mere metaphor for reality.

So what of recent attempts to explain the ultimate workings of the universe in terms either of a classical computer/computation, or, more recently, in terms of quantum computation?

Seth Lloyd, who works in the area of quantum computing, wrote a little book four years ago called Programming the universe. Lloyd claims that the universe is a quantum computer and we (and everything in it) are the computation. If this is true, then we are very privileged to be the first humans to have (half?) understood some very profound things about reality.

Lloyd recently reviewed in New Scientist a new book by Vlatko Vedral (Decoding reality) which makes the same claim and is clearly annoyed that Vedral does not acknowledge his book.

These issues are extremely complex and all I mean to do for the moment is to raise them. In my private reading I'll be following them up and I will report my progress (if any) from time to time. But I won't be writing on this sort of thing very often - others can do it better.

As things stand I am impressed with the view that information is a fundamental concept of physics, more fundamental even than the concepts of matter and energy. And if information is physical, then Seth Lloyd's arguments must be taken seriously.