0005

DU SIGNAL AU SIGNE

Henri Van Lier (1980)

L'univers comme histoire peut se diviser en trois grands moments. Au commencement était le signal, lequel règne depuis dix milliards d'années environ. Ensuite, voici trois ou quatre milliards d'années, s'est amorcé un second temps, qui a fini par provoquer une seconde origine: au commencement était le stimulus-signal. Enfin, voici quelques millions d'années, il y eut une troisième émergence, obligeant à dire: au commencement était le signe. Du signal au stimulussignal et au signe, il existe une continuité certaine. Mais entre le signal et le stimulus-signal, et entre celui-ci et le signe il y a également un abîme. Il faut s'arrêter aux deux premiers pour saisir l'originalité du troisième.

Dans les premiers temps du monde, ceux qui ont précédé l'apparition de la vie, il y avait bien déjà des événements, vu qu'il se produisait des différences, que ce soit de chaleur, de masse, d'énergie électromagnétique, de radioactivité, lesquelles faisaient que quelque chose avait lieu, que quelque chose se passait, arrivait. Et ces événements étaient déjà des informations au sens large du terme, puisque l'ordre qu'ils comportaient influençait d'autres événements, leur imprimait d'autres mises en forme, les informait. Il régnait donc également des signaux, c'est-à-dire des phénomènes physiques par lesquels les informations étaient transmises, depuis l'événement initial, informateur, jusqu'au phénomène final, informé. Ainsi l'univers était un théâtre avec des acteurs minuscules ou géants jouant des rôles: orages, bombardements de particules, réactions chimiques, faisant et défaisant les astres et les champs d'énergie.

Cependant, ce théâtre était sans spectateur. A moins qu'on considère les grands amas de matière comme des êtres doués d'une certaine unité organique, et pour autant d'une certaine conscience; les anciens et Leibniz pensaient des choses semblables, et leurs vues sont parfois reprises aujourd'hui par des astrophysiciens. En ce cas, les signaux charriant les informations d'un événement à l'autre auraient été, en un sens qui nous échappe, ressentis par divers foyers de l'univers; il y aurait toujours eu, et il y aurait toujours, dans l'immensité des phénomènes cosmiques, des acteurs et des spectateurs d'un genre particulier.

Quoi qu'il en soit, l'origine du monde et le signal ont pour nous partie liée. Ce qu'on appelle parfois l'horizon de l'événement est le lieu le plus éloigné d'où un signal puisse nous parvenir. On calcule cette distance. Il suffit de remarquer que l'univers est vieux d'environ 1010 années, et que le signal le plus rapide fait 300.000 km à la seconde, qu'il soit onde lumineuse ou onde radio. L'horizon de l'événement est ainsi à 1023 km de nous, et c'est donc dans un sens très rigoureux, articulé par un chiffre de temps et un chiffre d'espace, que l'on peut dire qu'au commencement était le signal.

Le stimulus-signal
Une première révolution fut introduite avec l'apparition de la vie, lorsque le récepteur du signal devint beaucoup plus complexe. Avant la vie, les amas stellaires et planétaires, ou les grands champs magnétiques et gravitationnels, même si on les suppose doués d'une certaine conscience, devaient disperser rapidement les informations particulières qu'ils recevaient; et les réactions chimiques avaient beau être déjà des réactions, c'est-à-dire comporter des actions en retour relativement stables et originales, les parts de l'informateur et de l'informé, de l'ensemble et des éléments, y étaient d'ordinaire très enchevêtrées. Au contraire, avec l'avènement du règne végétal, et plus encore du règne animal, l'information se fait précise et la réaction de plus en plus retardée et différenciée.

C'est pourquoi on a parlé dans ces cas, du moins quand ils sont suffisamment élaborés, de signaux stimulateurs, ou de stimuli-signaux. Un aigle qui fond sur sa proie est mis en branle par une information très déterminée: tel contraste de forme et de fond évoluant à telle vitesse; et cette information provoque, dans l'organisme et en particulier dans le système nerveux, des phases d'action chacune complexe. Dans cet exemple, c'est surtout les mouvements de la proie (le signal) et du prédateur (la réaction) qui frappent; mais dans d'autres ce peut être la transformation du milieu, comme quand les castors élaborent un gîte très sophistiqué. Encore les réactions des animaux ne se limitent-elles pas à ces performances totalement ou largement innées. A mesure qu'on monte dans les espèces s'accroît la capacité d'acquérir des comportements nouveaux, liés aux stimuli-signaux primitifs par des conditionnements et des renforcements; c'est l'apprentissage. Les singes mangent sans doute nativement des tubercules; mais lorsqu'une jeune femelle, dans le groupe des macaques de Kyushu, eut par hasard trempé des tubercules dans l'eau salée et qu'elle en eut trouvé le goût à sa convenance, cette innovation culinaire fut adoptée du moins par les singes jeunes, et ainsi inscrite dans la «culture» du groupe, au point d'être transmise aux générations suivantes.

Néanmoins, malgré leur richesse, les réactions aux stimuli-signaux et les comportements appris gardent dans leur déroulement quelque chose de fatal: comme le disent les éthologues, nous restons là dans l'ordre des déclencheurs, des releasers, directs ou indirects, inconditionnés ou conditionnés. Il n'intervient pas ou guère d'arbitraire, de convention, ni même d'approximation et de déplacements fréquents. Par exemple, des abeilles qui ont découvert des provisions font des danses qui stimulent leurs consoeurs à aller chercher leur provende dans telle direction, à telle distance, et en une troupe plus ou moins nombreuse selon la quantité repérée. Mais cela reste dans des suites obligées, celles-ci se modifiant seulement avec les variétés d'abeilles et les climats. C'est même trop de dire que les éclaireuses communiquent à leurs consoeurs un «message» de «distance», de «direction» et de «quantité». Elles déclenchent seulement une action collective appropriée, comme nous venons de le formuler.

C'est là que va survenir dans le cours du monde une révolution aussi décisive que l'avait été celle de la vie: l'apparition du signe, contemporaine de l'apparition de l'homme. Cette affirmation n'est pas ébranlée par le fait qu'actuellement on considère l'avènement de l'homme comme plus progressif qu'on ne l'avait cru d'abord, et qu'une fois le signe installé dans l'espèce humaine, des animaux puissent y être induits, comme en témoignent les éducations récentes de singes supérieurs, pour autant humanisables, on ne sait pas encore jusqu'à quel point.

0004

THE MIND'S EYE. HUMAN INTELLIGENCE IN A COSMIC CONTEXT

Timothy Ferris (1993)

When I think of the relationship between the universe and the human brain an image that comes to mind is that of a tree—not just its glorious crown of branches but also its system of roots, which may extend as far into the earth as the branches spread to the sky. To me, the branches symbolize the observed universe, while the roots symbolize the brain. Both systems are constantly growing and evolving, and they depend on each other. One might object that this makes too much of the roots: The brain, after all, is far less complex and extensive than the universe, which can get along fine without us. But the symmetry of the metaphor is preserved if we think of the branches as referring to the perceived universe. That universe exists only so long as there is someone to perceive it. Moreover, it is the only universe we can ever know. Neither we nor any other thinking beings can comprehend any more of the universe than what we can make of it in our minds. In that sense, roots and branches—mind and cosmos—are mutually dependent and forever equal. They are symmetrical, too, in that we tend to think of the universe and the brain as each being one thing.

0003

THE RED LIMIT. THE SEARCH FOR THE EDGE OF THE UNIVERSE

Timothy Ferris (1977)

This brings us, by a variant route, to a point we have considered before, that we owe our small existence to that of the broad universe. It suggests, in Wheeler’s words, “that there exists a degree of harmony between us and our surroundings that we never realized before. In the past, we looked at our surroundings as if there could be no other, something with which we just had to get along. If this new view is correct, our surroundings are very special and tuned to us, like a plant to its flower: This cycle of the universe like the plant, and we like the flower.” Through all science runs that refrain, that nature is intelligible to us because we in some sense belong to it. The scientist, wrote Einstein, “is astonished to notice how sublime order emerges from what appeared to be chaos.” Carl Friedrich von Weizsäcker told his friend Werner Heisenberg, “All our thinking about nature must necessarily move in circles or spirals; for we can only understand nature if we think about her, and we can only think because our brain is built in accordance with nature’s laws.” James Jeans wondered of the galaxies, “Do their colossal incomprehending masses come nearer to representing the main ultimate reality of the universe, or do we? Are we merely part of the same picture as they, or is it possible that we are part of the artist? Are they perchance only a dream, while we are brain-cells in the mind of the dreamer?” “Ultimately,” wrote Mach, “all must form one whole.” To say that nature is comprehensible, that science is not deluding itself, is an assertion of faith—“reason is one of the articles of faith,” said Eddington—but there is nothing wrong in that. After all, we are part of the universe. And the faith of science—that the seamless weave of nature will reveal itself to our reasoned inquiry—that faith is part of the universe too.

0002

THE MIND'S EYE. HUMAN INTELLIGENCE IN A COSMIC CONTEXT

Timothy Ferris (1993)

Each of us inhabits two equally mysterious universes, one outside the mind and the other within it. Since my youth I have tried to understand the relationship between these two realms. Many a night I sat at the telescope till dawn, marveling at the soft pewter glow of the distant galaxies, the glittering gold and silver star fields of the Milky Way, at sun-hugging Mercury, the pearl-white crescent of Venus, or the parchment-sharp rings of Saturn, and wondered what we have to do with all that.

 I have never shared the sentiment that the enormity of the cosmos need make us feel insignificant. The stars are too involving for that; they stimulate our curiosity, arouse us to reflection, nourish our sense of beauty, and challenge our conception of who we are. We feel connected to them, somehow. I do not think this intuition can be dismissed as mere sentiment, for the simple reason that we are able to some degree to understand what goes on out there. We know that iron oxide stains the ruddy sands of Mars, that helium atoms dance in the upper atmosphere of the sun, that storms dot the surface of Aldebaran, and that new stars are being born in the Tarantula nebula; we can predict eclipses of the satellites of Jupiter, weigh the great Catherine wheel of the Andromeda galaxy, take the temperature of Triton, and age-date the craters of the moon. Our knowledge of the universe amounts, of course, to an infinitesimal fraction of the whole, but the fact that we can learn anything at all about the stars suggests that thought—and maybe even “intelligence”—is not a purely parochial phenomenon, the product of our one world alone, but may have universal currency.

I envision our relationship to the universe as symmetrical,  ourglassshaped. On one side is the outer realm, inhabited by galaxies, stars, the plants and animals, and our fellow human beings. Most of us (the solipsists aside) believe that this outer world exists, though we appreciate that our direct perceptions of it are limited and skewed. On the other side is the inner realm of the mind, where each of us is destined to live and die; here resides all we can ever know. Through the neck of the glass flow the sense data by which we perceive the outer realm, and (flowing the opposite way) the models and concepts we apply to nature, and the alterations and abridgments we impose on her. We tip this imaginary hourglass from time to time. In the nineteenth century, when classical physics ruled, we tended to think of the sand as flowing almost entirely from the outer to the inner realm, from an objectively real world to our passively recording minds. In the twentieth century the concept of observer-dependent phenomena in quantum physics has shifted our attention to the ways our observations influence how we perceive nature. But so long as there are thinking beings in the universe, neither bulb of the hourglass will ever be empty.

In this book I offer a few thoughts on the relationship between mind and universe as seen through the lenses of two innovative fields of scientific research—neuroscience, and the search for extraterrestrial intelligence, or SETI.

Neuroscience has begun to reveal some fascinating things about how the brain works, shedding light on the concept of personal identity, the datahandling limitations of the central nervous system, and the way that the brain smooths over its liabilities and discontinuities to sustain a sense of unified consciousness. We are beginning to realize that each of us really does contain multitudes, as Walt Whitman put it, and that the chorus of voices within was built up over eons of evolution, like geological strata in the Burgess Shale or the White Cliffs of Dover.

SETI, meanwhile, has focused attention on what we mean by intelligence, and whether its like is to be found elsewhere in the universe. Regardless of whether we eventually succeed in intercepting an alien signal from space, SETI will have encouraged us to think about thinking in a cosmic context. In so doing it acts as a mirror; our ignorance of the role of life and thought in the universe forms the blacking on the back of the mirror.

(...)

The universe has four remarkable properties that encourage us to
investigate whether we are alone in the universe. The first is that space is transparent. A ray of starlight can speed unfettered through space for thousands of millions of years, bringing news of events long ago and far away, and the sailing is even clearer for radio waves. Natural radio noise—the chatter of hydrogen atoms adrift in space, the scream of electrons trapped in the magnetic fields of distant galaxies—can pass not only through the virtually perfect vacuum of interstellar space, but also though the clouds of gas and dust that clutter the disk of our galaxy and block the visible light of many stars beyond. These naturally occurring radio emanations need not be especially powerful for us to pick them up; all the energy gathered by all the world’s radio telescopes over the past thirty years amounts to less than the kinetic energy released by a snowflake falling gently to the ground. This suggests that artificial radio signals, too, could in principal be detected across interstellar distances, even if broadcast at modest levels of power. Radio telescopes in operation today could receive signals transmitted by similar instruments throughout much of our galaxy; a hundred billion stars and perhaps half a trillion planets lie within their range. And, since radio waves travel at the speed of light, three hundred thousand kilometers per second, their velocity of transmission is as fast as can be.

0001

SYMBOLISM: THE FOUNDATION OF CULTURE

Mary LeCron Foster (1994)

«Without symbolism there could be no culture. A symbol is an artefact: a ‘thing’ that exists out there somewhere in space and time. As a ‘thing’, a symbol has material reality and is experienced through the senses. It is a ‘thing’ that represents: that is culturally involved in such a way that it can be used in a multiplicity of contexts to convey meaning, not just about itself, but about cultural processes and relationships. Every symbol participates in a web of significances that we call culture. In other words, any symbol resonates with meaning. The meaning of a symbol is not a ‘thing’, and it can only be grasped inductively by observation of many instances of the social uses of that symbol, or similar symbols. It is only by observing praxis that ethnologists can discover cultural symbolic constructs, hence culture itself. Culture is not itself formed of symbols, but of the meaning that lies behind and unites symbols. This meaning only exists in the minds of participants in culture, but it is acted out through the manipulation of symbols, which objectify meaning. 

A single symbol is any entity that has socially participative meaning. Each symbol shares parts of its meaning with other symbols. It is this semantic resonance that underlies institutionalization, the preservation of socially constituted and conventionally manipulated networks of symbols. Culture is thus an elaborate system of classification whose units are symbols. It is a generalization from symbolic meanings shared within a society and realized during social interaction. 

The abstract system that is culture is founded on, and held together by, the human capacity to operate analogically. Networks of meaning constrain change in any part. This constraint contributes to cultural stability, but because the ability and drive to construct new analogies are omnipresent in the individual human biological heritage, change is also inevitable. Change is principally due to the creative human drive to readjust symbols—which means, in essence, to reorganize culturally transmitted analogical structures. Change was both slow and modest until the Upper Palaeolithic, which suggests that, until that time, symbolic organization was rudimentary.

The hallmark of culture, then, is institutionalization, founded upon classification, the symbolic organization of meaning. Each culture has evolved, and continues to evolve, through social experimentation in understanding, controlling, and utilizing, to its perceived advantage, sentient and insentient natural forces. The artefacts of culture, constituting the web that holds its institutions together, are symbols which are defined as the socially objectified loci of meaning.

Because symbols form a web of meaning for members of any given culture, no symbol has a meaning apart from the context of its relations with other symbols. To study symbolism it is necessary to examine and compare cultural contexts. This is the function of cultural anthropology. To understand symbolism as the foundation of culture it is also necessary to unravel the symbolic past.»