Brian Arthur's book is an analysis of how technologies arise and evolve.
Primitive technologies simply capture natural phenomena.
A primitive technology captures a natural phenomenon for the purpose of
exploiting it to achieve something that the natural phenomenon was not designed to do. (Arthur does not elaborate on the "metaphorical" value of this transfer
Often an invention is not a variation on an existing class of objects but a completely new object (for example, the jet engine). Technologies arise from other technologies, by combination of existing technologies. Technology as a whole is an autocreating organism. Arthur shows that the parallel with biological systems works only to a point. Biological organisms evolve by steady accumulation of small change, but technologies can appear all of a sudden. Once created technology indeed evolves according to Darwinian laws of variation and selection. The different between organisms and technologies is only in the way they are born.
The pyramid of technologies is mediated by knowledge. Knowledge leads to technologies that lead to more knowledge.
Domains of technologies define eras, define the very way we conceive of technology. An economy is a flow of goods and services mediated by technology.
Arthur mentions that technology determines our lives while it serves them, but does not elaborate on how technology shapes brains that invent new technologies. There is a neurological loop out there that is as important as the loop through knowledge.
On august 4 at Xerox PARC i heard a lecture by Brian Arthur that was probably more interesting and original than the book (Listen to it). Arthur discussed the silent, invisible economy that increasingly drives much of the developed world's services. That economy consists of a network of computers that nobody see. They interact and cooperate to provide a service in a few seconds. What we are witnessing in the new century is the rapid growth of the unmanned economy and the stagnation of the manned economy. This network is self-organizing, self-correcting and self-healing, just like the immune system and the brain. The hidden digital economy is becoming a brain. It is becoming "intelligent". This shadow economy relies on four entities: processors, sensors, actuators and linkages. Processors and linkages can be universal, but sensors and actuators (the interfaces with the world) are specific to each application.