Information, The Hidden Side of Life

Cédric Gaucherel, Pierre-Henri Gouyon, Jean-Louis Dessalles

• Publisher: Wiley-ISTE
• Year: 2018
• ISBN:
  9781119579359
• Edition: 1
• Topic: Informatique
• Subtopic: Technologies de l'information

This book explores the unity of life. It proposes that the concept of information is the inner essence of what we today call life. The importance of information for our species is obvious. Human beings are highly dependent on information, constantly exchanging with conspecifics. In a less apparent way, we are the product of genetic and epigenetic information which determines our development in a given environment from a fertilized egg to the adult stage. Even less apparent is that information plays a determining role in ecosystems. This observation may include the prebiotic systems in which life emerged. Our claim is that Nature processes information continuously. This means that even beyond living entities, we can see messages and decoding procedures. Nature can be said to send messages to its own future and then to decode them. Nature "talks" to itself! The systematic organization of messages suggests that, in some respects, we should even speak of the "languages" of Nature.

1
Human and Animal Communication

We, modern humans, find ourselves swimming in an ocean of information. If we were to get out of town to escape from the hubbub our fellow beings create, it may not be calm that awaits us in the forest. The forest has its own din, unceasing and of countless types. This is nature speaking to itself. Now, why should there be so much information being circulated, and so much time and energy being used up? This chapter discusses these questions, starting with the human case before going on to other languages in nature.

1.1. Language, that amazing thing

There are several ways in which Homo sapiens stand out from other species. Humans are bipeds, masters of fire, practitioners of art, makers of tools and weaponry, live well past the age of reproduction, impose rites of passage on each other between the stages of their life and so on. The human being is unique for many of these reasons. We differ from other primates in that we do not suffer from hirsuteness, and we walk on our rear limbs. However, there is another difference that, though rarely mentioned, is perhaps the most fundamental and the least anecdotal: Homo sapiens are information specialists. That is what this chapter is about, and we will also consider why this is the case.

Scientists of the 19th Century understood that Homo sapiens had not been created apart from other living beings, but was simply one among several species. Some, however, did not give up trying to find reasons for upholding our uniqueness, one way to try to regain our lost position. Many thoughtless assertions, such as “the human being is the only one to …”, have since been refuted. No, we are not the only ones to make tools; we are not the only ones to have a culture; we are not the only ones to know how to count. Chimpanzees and gray parrots can do some of these things. Saying that we do these things better, or that we can do more things than these, will not help save our ego as a species. The vanity evident in such beliefs is clearly unhealthy. It is a bit like the immaturity a child displays when they have not learnt that while they are unique, they are also equal to other children. In principle, difficult as it might be, the scientific approach should guard itself against the supposed uniqueness of the human species. At the same time, there is one striking fact we should not overlook.

Humans possess a characteristic that we may fail to notice, just as some of us may miss the elephant’s trunk when we look at the animal or the activity of the dam-building beaver. Humans talk. They talk a great deal. In fact, talking or listening take up one-third of our waking time, that is more than 6 h a day. On average, we speak 16,000 words daily. The males of some bird species perhaps do better quantitatively, but our words, endlessly repeated, create meaning; they produce information.

In the context of language, information has a somewhat precise intuitive meaning: we know whether what we are hearing is interesting or boring. Even though such a subjective feeling does not by itself provide a usable measure for the quantity of information contained in a particular portion of speech, it does point out a significant lead. It is by modeling how we spontaneously measure the appeal of another individual’s utterance that we can develop a general definition of the notion of information. This definition, though conceived in language, has applicability that extends well beyond.

1.2. The mechanics of language

Human communication is “monstrous” in several aspects, not only by the prohibitive amount of time devoted to it. Communication has requisitioned our memory and our intelligence. We know by heart tens of thousands of subtle shades of meaning found within words and expressions learnt during the course of our life. Any one of us can make an unlimited number of meaningful sentences using this lexicon, most of which may never have been uttered before. While we may be able to do this without much effort, we must not underestimate the intricacy of the mechanism involved. Language depends on incompletely understood processes, a study of which would be fascinating. The sentence “Last year, the alarm sounded when the birds flew overhead” provides illustrations of some of them. When we analyze the acoustic signal that reaches our ears, our brain recognizes some phonemes of English, the “l” of “Last”, then the long vowel “a:”, then the “s” and so on. The sentences contain about 30 phonemes. Some of them, like “s”, appear several times. These phonemes are drawn from a very limited set. English dialects offer a gamut of three dozens of them.

Why is it that there are so few phonemes? If there were more, every phoneme would have carried more information, our words would have been shorter and we would have been able to express numerically more ideas per minute. But this would have been at the cost of risking mounting confusion, because if we were to populate the accessible acoustic space of pronunciation with more phonemes, there would necessarily be a reduction in the acoustic contrasts that separate them. Then, why not enhance the acoustic contrast by utilizing fewer phonemes? After all, any computer scientist will tell you that two phonemes would do, as in Morse code. Yes, but then the words would grow longer, and they would flow more slowly. The English word “wonderful” is pronounced /’wʌndəfʊl/, and has eight phonemes, namely /w/, /ʌ/, /n/, /d/, /ə/, /f/, /ʊ/ and /l/. In the dot-and-dash Morse code, the word would read: dot dash dash space dash dash dash space dash dot space dash dot dot space dot space dot dash dot space dot dot dash dot space dot dot dash space dot dash dot dot, that is, 26 Morse signs and eight spaces. It is obvious that the two-phoneme code calls for a much longer stretch of time to transmit the word than the code composed of several phonemes within the acoustic space that our articulatory capacity allows us to access.

Phonology is a code that allows us to represent words in the form of sounds. Writing and sign languages are other codes that enable a representation of words. A code enables a transition from the domain of signs to the domain of meaning (Figure 1.1). The word “wonderful” may be coded by nine letters in writing, or by movements of the hand in the British sign language (both hands open, the index finger touching either side of the mouth, then moving forward and slightly outward). The meaning generated by these codes is the same.

Figure 1.1. A code enables a transition from the domain of signs to the domain of meaning

Some codes are word-for-word codes. This is the case with the code used by underwater divers (Figure 1.2). Here, the code has about 10 different gestures, each with a very precise meaning. For example, “I have just exhausted my reserve of air”. If there were no homophones in English, such as “hoard” and “horde”, or synophones, such as “fare” and “fair”, the phonological code would have been word-for-word.

Figure 1.2. The principal signs and their associated meanings in the code of underwater divers (http://www.aurel32.net/plongee/signes.php)

The divers’ code is not only word-for-word, but also holistic. In a holistic code, each sign is self-contained. It is not possible to break down the divers’ code into elements that could then be reassembled into new gestures to form another code. Most codes of communication among primates appear holistic, and cries used for different meanings generally do not have common parts (Cheney and Seyfarth 1990). We shall have more to say on this aspect later. Holistic codes, however, show one limitation: an entirely new sign needs to be invented for each new meaning. It happens that nature invented a far more efficient system that is at work in our languages, and also in the biology of our cells: combinatorial codes.

Figure 1.3. Combinatorial coding

In a combinatorial code, signs result from combinations of basic elements (Figure 1.3). The mechanism of combination is potentially capable of manufacturing a large number of signs. The phonological code is combinatorial: it manufactures its signs by combining phonemes. The word “wonderful” is encoded by a sign, /’wʌndəfʊl/, a combination of eight elementary phonemes. The system of traffic signs is combinatorial (Figure 1.4). The red circle stands for actions that are disallowed, the blue square for what is permitted and the red triangle warns of cyclists and other types of road user.

Figure 1.4. Examples of partially combinatorial code: traffic signs © Crown copyright

Computer codes use combinations of bits (a bit taking either of the two values 0 or 1) as elements to form “words” that encode instructions to the processor or addresses in the memory. Binary words such as these used to have 8 bits in the earliest personal computers, but are generally encoded with 32 or 64 bits in present-day machines. The elements of the genetic code (Chapter 2) are the four molecules denoted as A, U, G and C, and these constitute RNA.

It is possible to superimpose several levels of codes. This is the case with human language. The sets of phonemes or, in writing, the sets of letters encode words, or more generally morphemes – carrier units of meaning. The word “speaking”, for example, has two morphemes – a free morpheme speak-, the root, and a bound morpheme -ing, signifying a gerund form or a present participle. Sets of morphemes encode words according to the laws of morphology. In the above example, the two phonemes speak- and -ing together form the word speaking. Words, in turn, become elements of another code, the signs of which are phrases (nominal group, verbal group, etc.) and se...

Table of contents

• Cover
• Table of Contents
• Preface
• Introduction
• Acknowledgments
• 1 Human and Animal Communication
• 2 Genetic Information
• 3 Ecosystem and Information
• 4 Can We Define Information?
• 5 Evolution of Information
• References
• Index
• End User License Agreement