A relatively new field that has permeated its way into numerous other scientific, economic, and social science fields is network theory. As researchers have been focusing on complexity in our world, and how seemingly random connections between different entities can self-organize into something with structure, within the last decade or so some breakthroughs have been made that have helped in our understanding of such strange bedfellows as the Internet, World Wide Web, food webs, the spread of disease through social networks, how businesses live and die in the marketplace, and biochemical networks within our cells. Such completely different systems are linked together through the same mathematical organization, which is the basis of network theory.
A great introduction into the field is Albert-Laszlo Barabasi’s book “Linked.” Barabasi and his team discovered that the systems mentioned above (and more) are so-called scale-free networks. The idea is built around the concept of a hub, which is a node or component of a system that is linked to other nodes of the system. The World Wide Web, for instance, has as its nodes websites. There are, of course, billions of websites currently. But the vast majority of individual websites may only have a couple other websites that link to it. Only a very small number have large numbers of other websites that link to it. Some examples of popular websites are Yahoo, Google, CNN, and so on. These popular sites are hubs. Hubs essentially can be thought of as holding large portions of the network together. Problems can conceivably arise if a hub fails. The Internet is a similar sort of network with servers, personal computers, and routers as its hubs. A good summary article is in the May, 2003 Scientific American.
One can understand from this model how computer viruses are so effective and can spread so quickly around the world. If a single, typical node (perhaps my computer) is ‘infected’ by a virus sent out (normally via email) to the Internet, and if that node were to somehow contain it and not send an email out to anyone else, nothing would happen to the rest of the network. But if I were to send emails to a number of friends and acquaintances, or if the virus were sent to numerous nodes in the network, as each node sent out emails the virus spreads to each of those nodes, and before long it is possible to have a cascading effect. Now, if a hub is infected, and it is linked to many, many other nodes of the Internet network, large numbers of nodes of the Internet may be infected almost simultaneously, perhaps before an ‘antidote’ piece of software can be made available. On the other hand, let’s suppose hubs are ‘cured’ of a virus relatively quickly, but some of the small, peripheral nodes are infected. The virus is not extinguished just because hubs are cured. In fact, computer viruses can persist for long periods of time (6 months to as long as 14 months after antidote software is available) even without infected hubs because they can still move around, albeit slowly, between the poorly connected nodes of the network.
One interesting aspect of this is to think of a social network such as Al Qaeda. This organization follows scale-free network structures, rather than some other types of social network structures. Other types may be a hub-and-spoke structure like a dictatorship, where a central hub runs the entire network. A tree structure is also possible, with a set chain of command (much like a typical military organization, where more minor decisions can be made locally in parts of the network, and major, global decisions made by someone like the President or a top general, and this decision cascades down to lower parts of the network simultaneously. Al Qaeda is neither of these, but rather a ‘web without a spider.’ An analysis was done after the 9/11 attacks to determine the structure of the cell responsible for the attacks (this is outlined in Barabasi’s book). Mohamed Atta was indeed a hub of the suspected 34-person cell. But, he only had links with 16 other nodes. Marwan Al-Shehhi was linked with only 14 other members of the cell. Most of the other members only may have had one or two known links to other nodes, which is a signature structure for a scale-free network. If we assume the entire Al Qaeda organization is similarly structured, what we are fighting is indeed a network that is very flexible and can tolerate some number of internal failures. If Atta was captured prior to 9/11, that event would not have necessarily crippled the cell, and the attacks may have very well gone as planned. The reason is that the other nodes still had the links to hold together the cell, so even taking out the leader of the cell does not disconnect all the other links. Killing Bin Laden will not in itself cripple Al Qaeda for the same reason. In fact we have seen this because a number of Bin Laden’s very well-connected lieutenants (i.e. other hubs) have been killed or captured, and yet the attacks and killing by the periphery of Al Qaeda continue unabated. This is completely analogous to viruses in the Internet, where if a hub is ‘cured’ (i.e. Bin Laden removed) the virus may still be able to do damage through poorly connected nodes (small cells on the periphery of Al Qaeda’s network, acting almost independently). This is part of the power of a scale-free network structure.
If Al Qaeda had more of a military structure, taking out Bin Laden and some key lieutenants would likely cripple and possibly defeat the organization, much like taking out key generals in a war can have devastating consequences for the outcome of battles and perhaps the war itself. Unfortunately, it is not so simple with the terrorist organizations we are facing.
Thanks to Zenpundit for asking me to write up something on this. I am not an expert, but hopefully this helps in some small way for understanding bare basics of a network like Al Qaeda.