In Chapter 3 we suggested that there are basically two distinct ways of viewing the question of intelligence.

• First, there are the "structural" approaches which attempt to define intellect in terms of specific physical characteristics of neural equipment — brain mass, neurological complexity, and so forth.
• These were briefly discussed in that earlier chapter, and were found to be somewhat useful in comparing relative intelligence levels among the fauna of a single world (Earth).

But structural definitions are suspect in xenobiology because they tend to restrict the universe of discourse.

• While we hope that we have at least a vague notion of what intelligence does or ought to do, there may be many physiological — structural — ways of building a biological unit to do the same job.
• For this reason, probably the majority of xenobiologists would favor a functional definition of intelligence over a merely structural one.
• This would appear to be the only way to avoid the peculiarities and limitations of the mental organs found on Earth.

What is the best way to set forth a functional definition of sentience? Some writers have advocated a "checklist" approach.
The suspect creature should be carefully observed, they urge, and watched for signs of a specific constellation of behaviors from which smartness can be inferred.
Typical list items include:

• Faculty of reason
• Ability to fashion and use tools
• Proficiency with language
• Predisposition to learn from experience, or "mental plasticity"
• Forethought and equilibration
• Creativity, insight, and intuition
• Ability to transmit culture
• Sociability
• Use of logic
• Ability to symbol
• Curiosity
• Ability to perceive spatial, temporal, numerical, or abstract relationships
• Imagery and the ability to construct perceptual worlds
• Memory
• Self-awareness or consciousness

Such definitions, while perhaps adequately circumscribing the bounds of human intelligence (and this is questionable), actually tell us little about the nature of intellect as a general force in nature. Checklists tend to be anthropomorphic, culture-limited and starkly geocentric, and as such afford no real insight into the possible character of alien intelligence elsewhere in the Galaxy.

A somewhat more generalized intellect-defining behavioral hierarchy has been suggested by the well-known Harvard University entomologist Dr. Edward O. Wilson. He divides evolved intelligences into three distinct levels:

1. Lowest grade — the complete instinct-reflex machine. Representative organisms (sponges, coelenterates, flatworms on Earth) are so simply constructed that they must depend largely or wholly on token stimuli from the environment to guide them.
2. Middle grade — the directed learner. These organisms (arthropods, cephalopods, cold-blooded vertebrates and birds) have a fully elaborated nervous system with some programming, some learning. Typically it is narrow in scope and limited in responsiveness to a narrow range of stimuli. It results in behavior as stereotyped as the most neurally programmed "instincts."
3. Highest grade — the generalized learner. These organisms (humans, primates, social canids) carry a wide variety of memories, some of which have only a very low probability of ever proving useful. Insight learning may be performed, yielding the capacity to generalize from one pattern to another and to juxtapose patterns in ways that are adaptively useful. Few if any complex behaviors are wholly preprogrammed morphogenetically at the neural level. Perception of history, in the broadest sense, is a key feature.⁵⁶⁵

Wilson’s system provides an evolutionary progression, a standard against which extraterrestrials might theoretically be measured. Yet this definition — rather, identification — of intelligence suffers from many of the same weaknesses of the checklist approach. The fundamentals of thinking simply are not addressed.

Roger A. MacGowan, an aerospace computer scientist formerly at the Redstone Arsenal in Alabama, recognized that the key to understanding alien intelligence lies in data processing.⁷²⁹ The thinking process, he notes, consists of an arbitrary number of information-processing functions which may be carried out by living creatures. MacGowan selected five criteria which he believed to be both necessary and sufficient to specify intellectual functioning in any life-form in the universe:

1. Input — An organism must be capable of reacting to physical events occurring in its environment. If it has no sensory input, it has no information to process and thus cannot think.
2. Storage — Without the ability to remember, a creature could not learn. All data processing would have to proceed in real time, with full throughput and no delays. Such a being would perceive no past or future, merely an ever-present now. Since the primary function of life is to accumulate information and structure, it is hard to see how a creature without memory could possess an adaptive and useful intellect without recollection of the past.
3. Deduction — The ability to compare current input information patterns with stored information patterns is a crucial intellective function. By making such an association, the creature becomes able to respond to the present on the basis of its past. The ability to use the generalizations formulated yesterday to respond to the problems of today is of great selective value in the struggle for survival.
4. Induction — Inductive thinking must be considered a prerequisite for thinking, because it provides "a means of altering stored information patterns as a function of each input information pattern in such a way as to form or modify generalizations on the basis of experience." With induction, an organism is able to respond to its future on the basis of its past.
5. Output — After it has decided what to do, an intelligent being must act. This output may manifest itself either as physical or mental activity.

MacGowan’s criteria for intelligence, if we accept them at face value, are probably sufficient for the purposes of the First Contact Team. Yet they provide more identification than explanation of what intelligence does. Our search is not quite ended, but we sense that we are on the right track.

It is interesting to note that the processes of intelligence are remarkably similar to those of life itself. The methods used by brains to collect and order environmental information recapitulate the methods used by natural evolution.

To perform the functions suggested by MacGowan, for instance, brains or nervous systems must collect data, filter and reject irrelevancies, store and process that which is relevant, and then arrive at some conclusion based on the input stimuli.

• The techniques of natural selection are quite similar.
• Thousands, millions, or even billions of organisms — the "data bits" of evolution — are "fed" into the environment.
• There they are shuffled, ordered, discarded and selected according to fitness — that is, they are "processed" through the environment.
• The species as a whole picks up information thereby and collectively "learns" how to survive, storing the hard-won data in the community gene pool.

It is easy to view intelligence, on the one hand, as a kind of speeded-up evolution of sensory data, or to view natural evolution, on the other hand, as a "painstaking and slow, but implacable, intelligence."¹⁰⁰⁰

Life is a negentropic process that extracts order from the environment and stores it in a complex structure. How much alive is determined by how complex the structure is. Life is properly defined along a spectrum — the greater the data, the more alive the lifeform. Similarly, intelligence is a negentropic process by which information is extracted from the sensory data stream generated by stimuli in the environment. Again, we claim, the greater the data flow the smarter the lifeform. Intelligence, like life, cannot be defined in a yes/no manner but must be viewed in terms of a spectrum of functionality.

Even primitive protozoans have rudimentary neural apparatuses, and can be trained to do simple tasks such as swim up glass capillary tubes and cling to sterile platinum wires. More advanced creatures such as earthworms and snails are easily trained to perform more complicated "tricks." We find the glimmerings of higher intelligence in the most modest of Earth’s inhabitants, a striking example of evolutionary convergence on a grand scale which should provide some clue as to its ubiquity on other worlds.

Intelligence, indeed, seems as inevitable as life itself.³²⁴¹

We may perhaps glean some insight into the evolutionary processes underlying the emergence of intelligence by examining how human intellect arose on Earth.*

• While details may differ from planet to planet, the outcome of mental evolution elsewhere in the universe should be at least functionally similar.

* What is the optimum body shape for sentient ETs? Scientific opinion remains sharply divided on this question, and two schools of thought have emerged. The pro-humanoid camp (including Bieri,¹⁷⁰⁶ Blumrich,¹⁰⁵⁸ Campbell,¹³⁸⁰ de Camp,²⁵⁷² Fletcher,¹⁹³⁵ Howells,³³⁰ Hynek,⁵⁹⁷ Ley,²¹² MacGowan,⁶⁰⁰ Ordway,²⁵⁷¹ Puccetti,⁷¹ Rall,⁴⁴⁵ and Spall¹¹³⁷) claims that the primate form is best for tool-using aliens.

The non-humanoid camp (see Blum,¹⁶⁶⁸ Broms,¹¹⁹¹ Clarke,⁸¹ Dobzhansky,¹⁷⁰⁵ Eiseley,¹³⁵ Huygens,⁶⁰² Muller,¹¹⁸⁴ Oparin,¹⁵⁵⁸ Ornstein,³²⁷ Ruzic,⁵⁵⁹ Sagan,⁸⁵ Shapley,¹⁵⁵⁴ Simpson,³³⁴ Vertregt,¹¹⁷¹ and Wald⁸⁶⁷) holds that the human form is a unique evolutionary accident that will not be repeated elsewhere. (There is also a middle-of-the-road camp, such as Anderson,⁶³ Gardner,¹⁵⁵⁵ and Molton,¹¹²⁹ but this is a minor faction.) The debate has raged for decades, and will not be detailed here. Suffice it to say that the humanoid form is a very useful one, so it probably will not be rare. Whether it will be common remains an open question.

Figure 14.3 Information Stored in Genes, Brains, and Cultures Full Size

Any organism that must sense its environment and react to it, or seek mates and reproduce, or hunt for prey and avoid being preyed upon; or which has some form of locomotion or mobility probably will discover that added intelligence is of enormous benefit and selective value. In the game of life, smarter animals generally do better than dumber animals. Certainly one of the most interesting questions from the standpoint of xenology is: Will extraterrestrials have "advanced" intellect?

To the extent that intelligence is data processing, the more information a creature and process and store the smarter it is and the more competitive it will be in the struggle for survival on its home world during its natural evolutionary phase. The fundamental unit of information is the "bit," or binary digit, briefly discussed in the previous chapter in connection with sensory apparatuses. A bit, in the parlance of information theorists, is the amount of information needed to correctly choose between two equally likely answers to a simple yes/no query.

Let’s take an example. The English alphabet has 26 letters. If you play "Twenty Questions" with a friend who has some single letter in mind, it’s possible to guess which one it is by asking as few as five independent yes/no questions. (Try it.) Thus, theorists argue that a printed letter represents exactly five bits of information. The average five-letter word therefore has 5 × 5 = 25 bits, and so forth.

Figure 14.3 is a map of the various forms of biological information storage found on planet Earth. There are three curves, defining a clear progression from lower to higher capacity.

The lowest curve represents the amount of data stored in the genes of terrestrial organisms. Judging from its antiquity, genetic information storage appears to be the slowest, most time-consuming means available to living creatures. On timescales of millions of years, changes in the information stored per genome are imperceptible. Evolution evidently is a very slow intelligence.

The middle curve shows the storage of data in the brains of animals. This is a much faster process — large changes are readily apparent over time-scales of millions of years. The number of bits stored per entity, as well as the complexity of behavior, is greater with brains than with genes. Still, on timescales of millennia there is little change in the maximum quantity of information capable of being stored by a single biological brain.

The highest curve at the far right displays the amount of data stored in human cultures as a function of time. Sociocultural bit-storage is at once the most volatile and the most efficient technique, representing another quantum leap in overall capability. Change is rapid on timescales of millennia, and long ago surpassed the levels of the other two curves. In a sense, social evolution may be viewed as an extremely fast intelligence.

From these three curves, we may define three distinct orders of possible "advanced" alien sentience. Accepting tentatively the speculation that level of intelligence may depend in part upon the ability of an organism to assimilate information, we can imagine three distinct ways in which the quality of intellect may be worked out in biology. We shall call these "genetic sentience," "brain sentience," and "communal sentience," three steps along the path of ever-increasing intelligence.

Imagine an alien species which for some reason is trapped at the level of genetic information storage. Unable to progress to more efficient forms with higher data ceilings, the intellect of each individual entity is limited to what can be done with genes alone.

The insects of Earth are a case in point. It will be recalled that the majority of the animal world consists of invertebrates without notochords. instead, a network of smaller sub-brains called ganglia is used. The main brain in the head is merely a larger-than-normal aggregation of ganglia, so the basic system appears to be self-limiting as regards maximum size and complexity.

Finding the road to bigger brains — the next step up in intelligence — blocked, a few clever insects decided to make do with what little they had. Unable to become better at coping with the environment by individual intellectual effort, the social insect species (ants, bees, termites, etc.) reworked their genetic structures in order to increase their adaptability. Instead of storing information in their limited brains alone, they stored it in their genes. Their DNA, rather than their individual minds, learned.

Can we really say that the social insects are sentient, though? There is nothing wrong with this at all. If one considers the anthill or the beehive as a single superorganism — as do several xenobiologists⁵⁶⁵ — each clearly displays many of the attributes of higher intelligence:

• Data from the immediate environment are absorbed and acted upon.
• Judgments are made almost exclusively at the community level as regards:
• • foraging for food
• • reproductive activity
• • temperature and humidity control in hive or hill
• • military defense of the colony and so forth

And if sentience requires an ability to recognize the self, the social insect superorganism clearly meets this test.

• Colonies of ants or bees are acutely aware of their own identity.
• Individuals have no difficulty recognizing members of foreign colonies (even of the same species) as strangers.

In this sense, each nest is aware of itself as an entity or living system distinct from all others.

Many variations on this theme may readily be imagined from the vantage point of the xenological perspective. ETs with genetic sentience (often called “group intelligence”) may achieve communication between individual units in a wide variety of different ways. Ants respond strongly to pheromone (smell) signals, and bees to visual cues (e.g., the waggle dance). Aliens might choose auditory, tactile, magnetic or electrical* modes to achieve community-wide information processing and control.

Radioastronomer Ronald Bracewell has proposed a slime-mold colony with genetic sentience, which he disparagingly refers to as an "intelligent scum."⁸⁰ But there is no reason why individual members of societies with genetic sentience need be small and insignificant creatures, There may be valid evolutionary pathways that lead to genetic overspecialization before an advanced, self-aware brain can gain a foothold.

The result of such evolution might be a society of genetically distinct breeds within the main species, each specialized to perform specific societal functions — farming, construction, administration, recordation, soldiering — and each possessing a fairly complex technologically-capable mind without individual sentience. At least one modern psychological theorist has claimed that it is possible to think, calculate, and build complex technical civilizations without the capacity for individual self-awareness.²⁵⁹⁹

Science fiction writers Larry Niven and Jerry Pournelle created such an alien race in The Mote in God’s Eye.⁶⁶⁸ The extraterrestrial creatures in this novel had a diversity of different castes, determined genetically, for specialized forms of labor. The society was highly technological, despite the superficial resemblance to a termite colony, and was capable of radio, nuclear fusion, and interplanetary travel. Individual self-awareness, while apparently possessed by a few castes on a limited basis, was not the norm.

Genetic sentience and high technology, then, are not necessarily mutually incompatible.

* In Olaf Stapledon’s excellent science fiction novel Last and First Men,²⁵⁶⁷ the author describes the evolution of sentience among a collection of biological components which he calls “virus types." What appears to he a mere cloud of particles on the surface of Mars is actually a diffuse mass of physically separated units, whose intelligence arises through the integration of the whole by means of an electrical information transmission capability in the larger aggregates. The radio signals used by the human astronauts scramble the aliens’ "mind," precipitating an outbreak of hostilities. Dr. Thomas Gold also has suggested the possibility of a society of “electric ants” with “group intelligence” and immortal consciousness.²²

Genetic sentience involves a community of organisms that is aware of itself, but whose members are not individually aware. For such lifeforms, automatic behaviors and duty are all. To a social insect, each of its neighbors are virtually indistinguishable and fully interchangeable (within each caste or age grade). There is no sense of individuality; there is no word for "I." And with no sense of self there can be no sense of empathy for the selves of others — their thoughts, their drives, or their pain.

The brain sentient ET is aware of itself as a unique being different from all others. In the higher lifeforms, many subtle and complex clues are used to distinguish each of perhaps thousands of other local members of the species from the self. These distinctions are achieved without the penalty of genetic overspecialization. Much societal information is not "hard-wired" as in the social insects but rather is learned during childhood and possesses a flexible, or "plastic," nature.

• The lowest brain-toting creatures on Earth, such as fishes and amphibians, seem incapable of telling their own offspring apart from members of physically similar species which are their prey (the kids are eaten at birth if the parents happen to be hungry).

• Reptiles improve on this somewhat.²⁵⁶⁶
• However, it is mainly among the birds and the mammals — the two animal groups with the most highly evolved brains on this planet — that familial and social ties begin to be taken seriously.
• Many birds are known to have complicated pecking orders with dozens of independently identifiable animals in the chain.
• Among primates, particularly the chimpanzees, orangutans, and, of course, humans, xenologists find a developing or well-developed sense of the self²⁵⁶³ as well as a complex awareness of the individuality of others.

Possible variants of brain sentience, involving the concept of the triune brain. have already been discussed in an earlier section.

Communal sentience is difficult for human beings to imagine. ■ Just as insects can only be dimly aware of the implications of their tiny brains, ■ We humans can only vaguely appreciate the plethora of historical forces and sociocultural processes which circumscribe our social existence.

To them, humanity would appear at best partially conscious ■ Our continual relapses into states of war ■ Our dependence on elaborate, formalized and highly specialized institutions ■ Our lack of empathy with others would seem pitiful and barbaric.

Cultural information storage is clearly the most efficient and well-integrated technique available to biological lifeforms. As the graph indicates, it represents as great an improvement over brain-dependent systems as the brain represents over genetic systems. Sentience based on an internalized sociocultural awareness must be equally advanced beyond our own.³³²⁹

Beings with genetic sentience are physiological and social specialists.

• Both body and mind are strictly "mission-oriented."
• Individual initiative is stifled and behavior is stereotyped.

Brain sentient individuals have cast off the shackles of biological specialization.

• Members of these species are more or less physiologically generalized.
• Such creatures, of which humans are a typical example, are nevertheless forced to retain their social specialization patterns — pecking orders, dominance hierarchies, governments, etc.

Extraterrestrial species that have achieved communal sentience will be both physiological and social generalists.

• Not only will physical form be roughly equivalent throughout the society, but each individual member will be capable of handling virtually all sociocultural tasks with ease.
• While the individual members of a genetically sentient group are totally unconscious, and brain sentient humans are aware of themselves but not of their society, communal sentient aliens will have a well-developed, very real sense of their community as well as of themselves.
• Individuality need not be sacrificed: A new level of awareness is simply tacked onto the old.
• Somehow — perhaps by electronic telepathy or psychological synchronization — each creature can sense what is good for society just as a human knows that it is good to eat when he is hungry or to scratch when he itches.
• The alien feels personal anguish at offenses against the community, and perhaps even views it as a real, physical extension of his own body.

One wonders what such a race might think of us. To them, humanity would appear at best partially conscious. Our continual relapses into states of war, our dependence on elaborate, formalized and highly specialized institutions, and our lack of empathy with others would seem pitiful and barbaric. Just as humans can train a dog to perform certain useful tasks for purposes incomprehensible to the animal itself, perhaps communal ETs could teach us a few sociopolitical "tricks" to enable us to live together in harmony — though we understand them not at all.

The distinctions between the communal and genetic modes of sentience should perhaps be made more explicit. In a differentiated genetic society, the individuals are physically different from members of other castes and perform only very specialized physical and social tasks. In comparison, the communal society consists of individuals with similar bodies (no castes) and who perform highly generalized physical and social tasks. In the former, the individual member has no self-awareness whatsoever; in the latter, the individual has a deep and abiding (almost visceral) understanding both of his own self and of the corporeality of his society.

Communal sentience is difficult for human beings to imagine. Just as insects can only be dimly aware of the implications of their tiny brains, we humans can only vaguely appreciate the plethora of historical forces and sociocultural processes which circumscribe our social existence. The idea that alien beings may exist who can sense the pulse, the hunger and the mood of their community as easily as we can of our physical bodies is a mysterious and alluring possibility.

At last we arrive at the fascinating question of alien consciousness — whether it exists, what form it may take, and how advanced it may be. From our awareness of our own consciousness, we suspect it may be the most significant and unique aspect of the human thinking apparatus. Will ETs be conscious too?

Despite several millennia of avid theorizing, philosophers, theologians and psychologists still cannot agree exactly what consciousness is.

• The standard dictionary definition is fairly popular:
  "Consciousness is the awareness of one’s self as a thinking being."
• (Indeed it has been argued by some that the emergence of self-awareness represented the true dawn of humanity.²⁵⁶⁴)
• Other definitions abound, ranging from "awareness of awareness" to mere "wakefulness" or alertness.

According to Dr. Julian Jaynes, a Princeton University psychologist, most people feel that consciousness is the most self-evident thing imaginable about the human psyche:

We feel it is the defining attribute of all our waking states, our moods and affections, our memories, our thoughts, attentions, and volitions. We feel comfortably certain that consciousness is the basis of concepts, of learning and reasoning, of thought and judgment, and that it is so because it records and stores our experiences as they happen, allowing us to retrospect on them and learn from them at will.²⁵⁹⁹

Unfortunately, most if not all of these statements may be false. Consciousness does not appear to be a copy of experience, storing up experience, copying it like a camera to be reflected upon at some future time. Rather, suggests Jaynes, "conscious retrospection is the retrieval of what you have been conscious of before, and the reworking of these elements into rational or plausible patterns." Consciousness is not necessary for conceptualization either. One of the great functions of language, Jaynes says, is "to let the word stand for a concept, which is exactly what we do in writing or speaking about conceptual material, {which} we must do because concepts are usually not in consciousness at all." Similarly consciousness seems unnecessary for learning, which snails and flatworms can do. In fact thinking, judgment, verbal association, deductive and inductive reasoning, intuition, creativity and abstraction all do not require consciousness in order to be displayed by an intelligent lifeform. Concludes Jaynes:

Consciousness is a much smaller part of our mental life than we are conscious of, because we cannot be conscious of what we are not conscious of. How simple that is to say; how difficult to appreciate! It is like asking a flashlight in a dark room to search around for something that does not have any light shining upon it. The flash light, since there is light in whatever direction it turns, would have to conclude that there is light everywhere. And so consciousness can seem to pervade all mentality when actually it does not. … Consciousness does not make all that much difference to a lot of our activities. If our reasonings have been correct, it is perfectly possible that there could have existed a race of men who spoke, judged, reasoned, solved problems, indeed did most of the things that we do, but who were not conscious at all.²⁵⁹⁹

Consciousness, much like intelligence itself, appears to be an example of what is called an "emergent" by evolutionary theorists. According to Dr. James Grier Miller, President of the University of Louisville and a pioneer in systems science, more complex living systems at higher levels of organization manifest characteristics, more than the sum of the characteristics of the units which comprise them, not observed at lower levels.³⁰⁷¹ These new characteristics are emergents, made possible by the increased complexity present in higher-level systems. Dr. A.G. Cairns-Smith, Professor of Chemistry at the University of Glasgow in Scotland, describes emergents from the standpoint of biological evolution:

One can see natural selection as conserving and improving biological machinery. But this is far from the whole story: sometimes a quite new function is discovered, or some new way of performing an old one. Maynard Smith³³⁰³ has discussed how this can happen. He says: "This is a very common feature of evolution: a new structure evolves first because it confers advantage by performing one function, but in time it reaches a threshold beyond which it can effectively perform a different function." Lungs seem to have arisen through such a threshold, through fish finding another use for the esophagus — as an auxiliary respiratory organ. This set in train a series of modifications that was to lead, eventually, to the exclusive respiratory organs of animals. The "improving" aspect of selection was an essential part of the story, but lungs are not improved gills, they did not evolve through a succession of design modifications from gills. Lungs took over.

Objects often turn out to have uses other than that for which they were originally designed: headlamps are signals, books are flower presses, and so on. Indeed often a machine may be curiously well adapted to an inadvertent function, or a material developed for one purpose be found to have diverse uses. We might say that bone is stiff for load bearing functions, but this property was to be important too, in connection with efficient sound transmission, during the evolution of the mammalian ear. For higher evolution generally, such function ambivalence has not been simply an odd side effect. It has been part of normal strategy. Above all it has provided means of escape from initial design approaches.³³⁰²

Miller offers another clear-cut example of emergents by comparing three different electronic systems:

One of these — a wire connecting the poles of a battery — can only conduct electricity, which heats the wire. Add several tubes, condensers, resistors, and controls, and the new system can become a radio, capable of receiving sound messages. Add dozens of other components, including a picture tube and several more controls, and the system becomes a television set, which can receive sound and a picture. And this is not just more of the same. The third system has emergent capabilities the second system did not have, emergent from its special design of much greater complexity, just as the second has capabilities the first lacked.³⁰⁷¹

How does all this relate to consciousness? A number of scientists today suspect that the phenomenon of consciousness may be an emergent arising naturally from the organizational complexity and processing efficiency found in the human brain. Neurobiologists recently have delved more deeply into the workings of the brain, and many have concluded that a general physiological theory of human consciousness soon may be possible. Dr. Gerald M. Edelman, Nobel. prize-winning immunologist from Rockefeller University in New York, has made a tentative step in this direction.³⁰⁰⁵ At a 1977 meeting of more than a hundred neuroscience researchers in Colorado, Edelman outlined his theory.²⁵⁶²

The human thinking organ, he claims, is not infinitely malleable as previously supposed. Instead, there are a large number of different kinds of neural circuits hardwired into the brain. These respond to input from each of the senses like a tuning fork stimulated with resonant vibrations. The hardwired circuit groups consist of aggregates of from 50 to 10,000 individual neurons (the human brain has a total of about 10 billion), and together comprise the "primary brain repertoire."

According to Edelman’s theory, the primary repertoire responds when the message to which it is susceptible is received. Such receipt causes the neuron group to emit its own signal, which is recognized in turn by a second level of neural groups called the "secondary brain repertoire." The secondary level equipment, presumably since it receives greater amounts of compounded and pooled data, lies at a deeper level of awareness than the primary sensory hookups.

Consciousness arises when impulses and patterns generated by the secondary repertoire are cycled around and fed back in as fresh input for other units in the secondary repertoire. While the primary system only responds to direct sensory data from the outside, the secondary system can also respond to internally-generated data as if it were externally-generated. This self-monitoring effect, according to Dr. Edelman, gives rise to human consciousness because it allows a review of internal states. In other words, the brain can watch itself work.

Science fiction writers are fond of pointing out that there may exist many different levels of awareness among the extraterrestrial races of our Galaxy.¹⁵⁴³ Perhaps the most classic example of this may be found in The Black Cloud, written by astronomer Fred Hoyle.⁶² In the novel it is suggested that natural grades of consciousness may exist, and that it is virtually impossible for a being at one level to comprehend the mentality of another being at a higher level of consciousness. In a similar vein, Carl Sagan draws a fanciful analogy from our relation to the insect world:

The manifestations of very advanced civilizations may not be in the least apparent to a society as backward as we, any more than an ant performing his anty labors by the side of a suburban swimming pool has a profound sense of the presence of a superior technical civilization all around him.¹⁵

These writers may not be far of the mark, for it appears quite possible that a variety of different grades of awareness may emerge at successively higher levels of organization and processing capability. Why is this so?

The essential characteristic of all intelligent systems constructed of matter-energy is that they process information. As noted earlier, smarter lifeforms tend to survive more often than dumber ones, so we should observe a strong evolutionary trend toward increasing intellect. Translating this into the language of information theory, we might say that the more bits per second a given creature can process, generally the more successful it will be and the stronger the evolutionary pressure to increase the bit rates that brains can handle. Furthermore, since more efficient organisms preferentially survive, all else being equal, there should also exist strong evolutionary tendencies to increase the efficiency of information processing — that is, to process more information using less energy and less material supportive bulk.

If these notions are basically sound, then xenologists may define a "figure of merit" applicable to all sentiences in the universe, one which expresses both capacity and efficiency in a single number. This we shall call the Sentience Quotient (SQ). It is expressed. as the log₁₀ of the quotient of two numbers: The maximum bit rate a sentient creature can process per unit time interval (in bits/second), divided by the quantity of mass-energy the entity needs to do it (in kilograms).

What is the theoretical maximum SQ of any thinking entity in the universe? While this question may at first appear intractable, actually it is not. According to H.J. Bremermann, if energy levels are used as information markers (the most efficient markers imaginable) then the theoretical maximum amount of information that can be processed by a totally dedicated lump of matter is 1.4 × 10⁵⁰ bits/sec-kg.³⁰⁷² (See further discussion in Section 25.2.2.) An alien being capable of handling data this rapidly would have to be considered a "perfectly efficient" thinker. In any given mass category, such an entity would possess the greatest intelligence theoretically possible in this universe. Hence, the highest SQ is about log₁₀(1.4 x 10⁵⁰) ~ 50.

Consider, as a purely speculative hypothesis, that there may exist a natural order of awarenesses in the cosmos. At each higher level of mentality, a new kind of thought process emerges which is unique to mental systems of equal or higher values of SQ. That is, there may exist a number of higher-order intellectual emergents, analogous to but qualitatively vastly superior to consciousness.

Table 14.1 Universal Scale of Sentient Emergents

What might these higher-order emergents be? The author’s own speculations are offered in Table 14.1. According to this scheme, the most primitive emergent of intelligence is simple "reactivity" — the differentiation of body cells into specialized cells whose sole function is data processing. Perhaps this requires a minimum of 1 bit/sec-kg in the most primitive organisms.

Consciousness of the human type is the next highest emergent. Human brains have about 10¹⁰ neurons with about 10³ interconnections each and a bit rate on the order of 10³ bits/sec/neuron.³⁰⁷¹ But brains have tremendous redundancy; assuming a redundancy of 1:10⁴ and a body mass of about 100 kilograms, the human organism works out to about 10¹⁰ bits/sec-kg,³²³³ or SQ ~ 10. This seems near the minimum for the emergence of consciousness.

Taking similar steps of ten orders of magnitude for each new emergent to appear, at least four successively more sophisticated mental classes should exist above the level of ordinary human consciousness.

• The first of these is "communality," or the emergent of communal sentience discussed earlier in this chapter (14.2.3 Communal Sentience), perhaps at the 10²⁰ bits/sec-kg level.
• Second could be "hypersociality," a yet higher order of mentality capable of internalizing the processes, functions, and interrelationships between many different societies and species of sentient beings (10³⁰ bits/sec-kg).
• Third might be "galacticity," a single creature’s comprehension of the complexities of a galactic community (10⁴⁰ bits/sec-kg).
• Finally there could be "universality," the ability of a single sentient entity to hold in its mind the seemingly incalculably complex orderings of an entire universe – full of living systems at all levels of intellectual sophistication (10⁵⁰ bits/sec-kg).

Naturally, at each higher level of data processing fewer data may be processed at that level. For instance, human consciousness can only handle in formation at about 0.1-1.0 bits/sec-kg,³⁰⁷¹ even though our brains may be able to process reactivity (nonconscious) data at much higher rates. Note also that a conscious brain-based entity such as a human can only process communal-level data at the rate of 10^-10 bits/sec-kg (because communality has not yet emerged), which perhaps helps to explain why humans have such great difficulty comprehending the intricate workings of the societies in which they live. Finally, note that an intelligent entity at any one level should also possess all simpler levels of awareness as well. Thus for example an hypersocial sentient ought to have communality and consciousness as well as simple reactivity.

Further implications of the Sentience Quotient concept in "first contact" situations are explored in greater detail in Section 25.3.