When I consider the effect of the Internet on my thought, I keep coming back to the same metaphor. What makes the Internet fundamentally new is the many-to-many topology of connections it allows: suddenly any two Internet-equipped humans can transfer essentially any information, flexibly and efficiently. We can transfer words, code, equations, music or video anytime to anyone, essentially for free. We are no longer dependent on publishers or media producers to connect us. This parallels what happened, in animal evolution, as we evolved complex brains controlling our behavior, partially displacing the basically hormonal, one-to-many systems that came before. So let's consider this new information topology from the long evolutionary viewpoint, by comparing it to the information revolution that occurred during animal evolution over the last half-billion years: the evolution of brains.
Our planet has been around for 4.5 billion years, and life appeared very early, almost 4 billion years ago. But for three quarters of the subsequent period, life was exclusively unicellular, similar to today's bacteria, yeast or amoebae. The most profound organic revolution, after life itself, was thus the transition to complex multicellular organisms like trees, mushrooms and ourselves.
Consider this transition from the viewpoint of a single-celled organism. An amoeba is a self-sufficient entity, moving, sensing, feeding and reproducing independent of other cells. For three billion years of evolution, our ancestors were all free-living cells like this, independently "doing it for themselves," and were honed by this long period into tiny organisms more versatile and competent than any cell in our multicellular bodies. Were it capable of scorn, an amoeba would surely scoff at a red blood cell as little more than a stupid bag of protoplasm, barely alive, over-domesticated by the tyranny of multicellular specialization.
Nonetheless, being jacks of all trades, such cells were masters of none. Cooperative multicellularity allowed cells to specialize, mastering the individual tasks of support, feeding, and reproduction. Specialization and division of labor allowed teams of cells to vastly outclass their single-celled ancestors in terms of size, efficiency, and complexity, leading to a whole new class of organisms. But this new organization created its own problems of communication: how to ensure smooth, effective cooperation among all of these independent cells? This quandary directly parallels the origin of societies of specialized humans.
Our bodies have essentially two ways of solving the organizational problems raised by coordinating billions of semi-independent cells. In hormonal systems, master control cells broadcast potent signals all other cells must obey. Steroid hormones like estrogen or testosterone enter the body's cells, penetrating their nuclei and directly controlling gene expression. The endocrine system is like an immensely powerful dictatorship, issuing sweeping edicts that all must obey.
The other approach involved a novel cell type specialized for information processing: the neuron. While the endocrine approach works fine for plants and fungi, metazoans (multicellular animals) move, sense and act, requiring a more subtle neural form of control. From the beginning, neurons were organized into networks: they are teamworkers collaboratively processing information and reaching group decisions. Only neurons at the final output stage, like motor neuron, retain direct power over the body. And even motor neurons must act together to produce coordinated movement rather than uncontrolled twitching.
In humans, language provided the beginnings of a communicative organizational system, unifying individuals into larger, organized collectives. Although all animals communicate, their channels are typically narrow and do not support expression of any and all thoughts. Language enables humans to move arbitrary thoughts from one mind to another, creating a new, cultural level of group organization. For most of human evolution, this system was very local, allowing small bands of people to form local clusters of organization. Spoken language allowed hunter-gatherers to organize their foraging efforts, or small farming communities their harvest, but not much more.
The origin of writing allowed the first large-scale societies, organized on hierarchical (often despotic) lines: a few powerful kings and scribes had control over the communication channels, and issued edicts to all. This one-to-many topology is essentially endocrine. Despite their technological sophistication, radio and television share this topology. The proclamations and legal decisions of the ruler (or television producer) parallel the reproductive edicts carried by hormones within our bodies: commands issued to all, which all must obey.
Since Gutenberg, human society has slowly groped its way towards a new organizational principle. Literacy, mail, telegraphs and democracy were steps along the way to a new organizational metaphor, more like the nervous system than hormones. The Internet completes the process: now arbitrarily far-flung individuals can link, share information, and base their decisions upon this new shared source of meaning. Like individual neurons in our neocortex, each human can potentially influence and be influenced, rapidly, by information from anyone, anywhere. We, the metaphoric neurons of the global brain, are on the brink of a wholly new system of societal organization, one spanning the globe with the metaphoric axons of the Internet linking us together.
The protocols are already essentially in place. TCP/IP and HTML are the global brain equivalents of cAMP and neurotransmitters: universal protocols for information transfer. Soon a few dominant languages like English, Chinese and Spanish will provide for universal information exchange. Well-connected collective entities like Google and Wikipedia will play the role of brainstem nuclei to which all other information nexuses must adapt.
Two main problems mar this "global brain" metaphor. First, the current global brain is only tenuously linked to the organs of international power. Political, economic and military power remains insulated from the global brain, and powerful individuals can be expected to cling tightly to the endocrine model of control and information exchange. Second, our nervous systems evolved over 400 million years of natural selection, during which billions of competing false-starts and miswired individuals were ruthlessly weeded out. But there is only one global brain today, and no trial and error process to extract a functional configuration from the trillions of possible configurations. This formidable design task is left up to us.