The Five Knowledge Storage Media
This was the core topic of both my book (The Laws of Software Process) and the column I published in ACM’s Communications of the ACM for 18 years. It’s quite a simple concept and it is based on the answers to the question:
Once we have acquired knowledge, where can we put it?
I spent good part of my professional career teaching software engineers, managers, and executives what it takes to effectively build software and to make sure it works. In the process of explaining certain characteristics of “software” to both people whose job it was to build the stuff and to those people responsible for managing the people who build the stuff, certain things about the stuff became evident.
The main thing that became evident to me was the answer to the question above—once we have knowledge, where can we put it? What media can we use to store knowledge [1]?
It turns out that, once we have knowledge, there are only five places we can put it. The first chronological medium in which knowledge was/is/can be stored is:
DNA
This is where species store the knowledge of what it takes to be a member of the species: what its parts are, how it grows, how it acts, how it reproduces,… Knowledge is placed into DNA largely through a process of evolutionary mutation. Once the “correct” knowledge is “correctly” [2] inserted into DNA, this knowledge, fed through the survival and subsequent reproduction process (which is also stored in DNA) can create a new instance of the species that also has access to that knowledge.
Sheep herding border collies "know" how to herd sheep, almost without being trained. We humans do not have to go to school to learn how to make our pancreas function—this knowledge is intrinsic to the body—it is stored in our DNA. For most animals, humans included, most physical functions and any behavior we call “instinctive” is DNA-stored knowledge.
DNA probably appeared on the Earth around four billion years ago.
FOOTNOTES
[1] This question had been rattling around in my mind for a while. Then, in the early 1990s, while I was on a plane traveling from Hong Kong to Los Angeles I read Peter Drucker's book Post Capitalist Society. He pointed out that the age of capital (ie., money) was over and we were now in the age of knowledge. This was the ah-ha! moment when I thought, ok, but once we've got it, where could we put it?
[2] Of course Charles Darwin’s contribution to this “correctness” test was the teleological observation that the mutations that were most effective in allowing the DNA carrier to survive and reproduce were those mutations that survived and reproduced. The “Survival of the Fittest” label is really the “Survival of the Fittest to Survive in the Environment.” So, in this case, the qualification process mentioned earlier is survival and the benchmark source is the environment. There are a great many species of animals and plants that have lived and thrived on the Earth—that “passed the test”—until the benchmark changed and then they didn’t.