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8 Expanding Our Perspective
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8 Expanding Our Perspective 1 The Distribution of Intelligence in the Universe The weight of the evidence, as surveyed in the preceding chapters , indicates that conscious intelligence is a wholly natural phenomenon. According to a broad and growing consensus among philosophers and scientists, conscious intelligence is the activity of suitably organized matter, and the sophisticated organization responsible for it is, on this planet at least, the outcome of billions of years of chemical, biological, and neurophysiological evolution. If intelligence develops naturally, as the universe unfolds, then might it not have developed, or be developing, at many other places throughout the universe? The answer is clearly yes, unlesstheplanetEarthisutterlyuniqueinpossessingtherequired physical constitution, or the required energetic circumstances, such as a benignly warming sun fairly close by. Is it unique in the relevant respects? Let us examine the evolutionary process, as we now understand it, and see what the process requires. Energy Flow and the Evolution of Order Basically, intelligence requires a system of physical elements (such as atoms) capable of many different combinations, and a 262 Chapter 8 flow of energy (such as sunlight) through the system of elements. This describes the situation on the prebiological Earth, some 4 billion years ago, during the period of purely chemical evolution . The flow or flux of energy, into the system and then out again, is absolutely crucial. In a system that is closed to the entry and exit of external energy, the energy-rich atomic combinations within the system will gradually break up and redistribute their energy among the energy-poor combinations until the level of energy is everywhere the same throughout the system— this is the equilibrium state. Like water in a gravitational field, one might say, energy ‘seeks its own level’. It tends to flow ‘downhill’ until its level is everywhere the same. This humble analogy expresses the essential content of a fundamental physical law called the Second Law of Thermodynamics : in a closed system not already in equilibrium, any energy exchanges tend ruthlessly to move the system toward equilibrium, that is, toward a state in which the total energy within the system is distributed equally among all of the parts of the system. And once a system has reached this lowest or equilibrium state, it tends to remain there forever—a uniform, undifferentiated murk. The formation—within that system—of complex, interesting, and high-energy structures is then profoundly unlikely, since that would require that the system’s internal energy distribution flow back ‘uphill’ again. It would require that a significant energy imbalance spontaneously appear within the system. And this is what the Second Law effectively prohibits. Evidently, the evolution of complex, energy-storing structures is not to be found in such a closed system. If the system is open to a continuous flux of energy, however, then the situation is completely transformed. For a schematic [3.92.96.247] Project MUSE (2024-03-28 13:36 GMT) Expanding Our Perspective 263 illustration, consider a glass box, full of water, with a constant heat source at one end, and a constant heat sink (something to absorb heat energy) at the other, as in figure 8.1. Dissolved in the water is some nitrogen and some carbon dioxide. The right end of the box will grow quite hot, but as fast as the fire pours energy into this end of the system, it is conducted away toward the cooler end and out again. The average temperature inside the box is therefore a constant. Consider the effect this will have on the thin soup inside the box. At the hot end of the box, the high-energy end, the molecules and atoms absorb this extra energy and are raised to excited states. As they drift around the system, these energized parts are free to form high-energy chemical bonds with each other, bonds that would have been statistically impossible with the system in global equilibrium at low energy. A variety of complex chemical compounds is therefore likely to form toward the hot end of the system, and to collect toward the cooler end, compounds of greater variety and greater complexity than could have been formed without the continuous flow Figure 8.1 264 Chapter 8 of heat energy through the system. Collectively, carbon, hydrogen , oxygen, and nitrogen are capable of literally millions of different chemical combinations. With heat flux turned on, this partially open or semiclosed system starts vigorously to explore these combinatorial possibilities. It is easy to see that a kind of...