This past weekend I attended DragonCon – mainly to participate in the science and skeptics tracks. It is a great outreach program, teaching the science behind science fiction. I sat on one panel that discussed the science of zombies. Zombies, for whatever reason, are currently very popular. Similar to the panel idea, the CDC has exploited this popularity to promote disaster preparedness – preparing for a zombie attack is the same, essentially, as preparing for any natural disaster. It’s a good hook for public service information.

One point that came up on the panel was the consequence of a zombie apocalypse, specifically if the vast majority of the population are now dead (or undead, or at least seriously brain-damaged), how will we reboot civilization after the zombies are defeated. This is an interesting thought experiment.

My fellow panelists spoke about where to find stores of information that would likely have survived, such as rural university libraries. It is a good thing that we still print books and journals in large numbers. After any apocalypse such hard copies will be our best source of technical and scientific information. Well – perhaps our second best source. The best source will be surviving experts. That, of course, will also be the very problem – the loss of most experts.

Clearly there will be a massive loss of expertise, and how many survive will depend on how much of the population is killed. If 99.9% of the population is killed, then probably 99.9% of experts will be killed. This will be the greatest challenge to rebooting civilization.

There are several factors to consider. The first is the number of areas of expertise. We may think of doctors, physicists, and engineers, but actually within each of those fields there are dozens of general areas of expertise, and hundreds of areas of subspecialty. In every discipline there are several layers of greater and greater, yet narrower and narrower expertise. Chances are, most of the narrow focuses of expertise will be lost in the apocalypse. We would be left with a random scattering of knowledge.

There are also many areas of knowledge of which you may not even be aware, and some that are mere hobbies in modern society but will become essential to a civilization reboot. Blacksmiths, woodwrights, and hunters may be mostly hobbyists, but in a post-apocalyptic world their skills will likely be essential.

Another factor is the dependence of many modern experts on the infrastructure of civilization. As a neurologist practicing in a developed country, my skills and knowledge are highly dependent upon our modern technological society. All of my knowledge of MRI scans, DNA testing, and even pharmaceuticals may be useless in a post-collapse world that lacks all of these things. I would also lack the support of all of the subspecialists on whom I currently rely.

Finally, we need to consider the relative value of the knowledge contained in textbooks and journals vs the uneaten brains of surviving experts. My sense is that there is a tendency to overestimate the value of the knowledge contained in books, and grossly underestimate the value of the training that experts receive. In other words, most people cannot become an expert in a highly technical field, especially an applied science or engineering field, simply by reading books. You may become highly informed, but not a world-class expert.

There is an unbroken chain of knowledge and experience that is passed down from teacher to student – subtleties, nuances, and context that are not fully explored in any text. This is why countries or even universities can maintain a dominance in a field over generations, because their chain of experts is better than others, and this cannot be easily recreated, even with access to the world’s journals and texts on the subject.

Breaking the chain of knowledge would represent a permanent loss of information and expertise to our species. It can be recreated, of course, but that will take time. The lost knowledge would have to be regained through practice, study, and new experience. How long this will take will depend on how much of the population is left. This relates to one further factor to consider – our collective knowledge largely rests on the shoulders of rare geniuses. When the human population numbers in the billions, there are many potential experts who are true geniuses, that have insight and a grasp of their area that is beyond the average expert. And they will typically share their insights with their colleagues and students.

If we had to recreate civilization with mere millions rather than billions, there would be fewer such people around. So recreating areas of expertise – reforging that chain, would be even more difficult. It may take centuries to get back to where we were before the collapse.