Once begun, life continued—exploiting, growing, replicating and diversifying, extracting energy from disorder, being occasionally knocked back many stages as environmental catastrophes occurred, eventually to arrive as we find it today. This continuous pattern is all that has been needed for life to become first, ever more complex, and second, ever more intelligent, as we will see.
The majority of life forms that populate this planet today are incredibly more complex than those that existed a billion years ago. Of course, ever since Darwin proposed his theory of evolution we have known why organisms become more complex. Since most changes are merely modifications to an existing structure, their incorporation adds another layer to that structure. Complexity results, simply because amendments are necessarily added to what has existed before. Many of the old abilities remain, most still active underneath—the new ones simply extend the entity’s capabilities.
But before they can serve any useful purpose, many changes in body structure and functioning have first to be controlled and directed. A slight increase in finger length or joint flexibility, for instance, offers no survival benefit at all unless the animal can manipulate the modification to gain an advantage over its competitors. This almost always calls for an increase in physical or body-activating skills, which in turn call for an increase in the mental skills needed to manipulate body parts, or to utilize improvements in sensory perceptions.
Motor ability does not come out of the blue; in the modified finger example above, the change requires controlling by finger, wrist, and/or arm muscles, which in turn have to be exerted in new ways. As an example, random poking into crevices to extract bugs or maggots would flex and train these muscles, and this activity feeds information to the brain. Over time, the brain learns which incoming stimuli have been produced by which finger movements. Sooner or later, the brain reverses this process, sending impulses to a specific finger to produce the desired results. Thus, a genetic mutation that caused a body change has led to a new skill being learned, a result noted in the previous chapter in the suggestion that the evolutionary process itself has evolved due to an animal’s ability to learn.
Yet the increased mental capacity is not inheritable. The animal’s offspring learn, through observation, repetitive play and practice, how to use their body’s abilities. Other times, as often with humans, they are deliberately taught. What is learned is stored via synapse development between the brain’s neurons, and becomes part of one or more of the animal’s mental constructs. Infants’ brains explore the body’s capabilities and limitations; they learn what can be controlled by attempting many movements and activities. Additional, mutation-created, physical capabilities require additional, learned, mental capabilities, to obtain this control. As noted in The Mind, learning (linking the information held within neural networks) and intelligence are different aspects of the same phenomenon. Thus, evolution trends toward intelligence simply because a greater intelligence is needed to control a more complex body.
Intelligence is the ability to solve problems, i.e., in earlier terms, the ability to recognize new relationships amid the memories and stimuli present within the mind, to make new neural connections, then to apply this new understanding in some useful way. It is not the mere possession of a large storehouse of facts, theories, or knowledge. These are just the material, the nuts and bolts, with which intelligence works to build theories and constructs, to solve problems and make decisions. Knowledge can be lost in one generation; intelligence cannot.
Two points must be emphasized. First, evolution trends toward complexity and intelligence, not toward humans. There is nothing inevitable or sacrosanct about our current dominance on this planet. Any language-using species will develop a similar intelligence, given time, although that species’ morphology and history would likely nudge its intelligence to develop in different directions from ours. Second, the fact that intelligence develops is not evidence that life has been directed toward it. Life evolves the way it does solely as a consequence of the physical parameters present at the universe’s birth, those that have structured every item and every event since that time. This accounts for all that exists and all that occurs. Intelligence is no different from other phenomena and needs no other kind of explanation.
- A billion years ago was near the end of the Proterozoic Eon, when bacteria, prokaryotes, eukaryotes and multicellular organisms existed in the oceans, but the lands were barren. See Development Of Life On Earth for a little more detail.
- This is why, to quote Ernst Haeckel (a German biologist, 1834-1919), “ontogeny recapitulates phylogeny,” i.e., fetal development restates evolutionary history. Presumably, research will show gene expression successively turning on stored instructions in the same sequence as evolution changed the species. (This also suggests that, sooner or later, body structures become so burdened by their out-grown history that radical change—evolutionary surgery—occurs, and gene expression is turned off.)
- The brain is a clear example of this. The cerebrum, considered the seat of intelligence where the brain’s most complex functions (i.e. problem solving) are carried out, is outermost. The cerebellum (which co-ordinates movements) and the medulla (which helps to maintain respiration and other involuntary functions) lie underneath, on either side of the thalamus (which directs all sensory signals—except smell sensations—to and from the brain). The hypothalamus (which regulates many basic body functions such as temperature control, sexual and emotional behaviour, urges to eat and sleep, and so on) lies near the centre of the brain. And at the core, the central brain stem carries out the most basic and primitive tasks—those of regulating heart rate, blood pressure, regurgitation and respiration, as well as conducting electrical signals to and from the body’s organs and systems. This construction demonstrates how one complex body structure, the brain, has been formed: modifications that proved useful to survival were outgrowths of earlier ones.
- Brain imaging provides physical evidence that this occurs. As different portions of the brain control different body functions, imaging its pattern of electrical activity reveals which functions are being called upon. Using this technique, it has been found, for example, that the brains of violinists grow unusually high numbers of synaptic connections in the area which controls the finger movements of the left hand.
- Applying new understanding may be as mundane as filling in a box on an IQ test sheet, as overlooked as recognizing a face in a crowd from an earlier chance meeting, or as practical as designing a bridge. Intelligence is expressed through actions that result from biochemical flows through neural links consciously formed by an animal.