As political actors, human beings are composite, not monolithic. We are consistently variable, and there are plenty of ways in which we actively enjoy this. No one likes to feel that they are beyond persuasion, i.e. beyond the capacity for judgement. Nor does anyone like to feel that they are purely in the grip of their own, crude self-interest; we treasure the idea that we can serve higher purposes, show loyalty to others, have strong convictions, serve the community and so forth. All of these attributes, though, are just milder versions of the things that drive fanatics.
Fanatics have strong internal motivations, but they also have very strong, usually distorted views about what other people think, and even what other people really are.
Take the gradient/spectrum of patriotism and nationalism. Patriotism is attachment to one’s homeland, love for its distinctive scenery, flora, fauna, customs and so forth. Patriots like their own countries best, and by extension they like the people who live there. This does not involve harbouring resentful thoughts about other countries.
Contrast this to nationalism, which carries all the same loves of land and folk, but with an additional abstract layer concerned with rights, conferred by the mere possession of territorial locality and heritage. Patriots may or may not have a generalised dislike of foreigners in their country, but nationalists can express this feeling as a matter of rights, not interests or opinions.
Once the idea that a nation has the right to rule itself takes hold, the idea that this right might be taken away or flouted can also take root, and after that, enemies are not difficult to identify. Nations are set up in competition as a natural by-product of national distinctions. Fanatical nationalists, who have been responsible for an enormous amount of the world’s terrorist atrocities, are only a little further along this line.
Fanatical beliefs are not very different from standard ones. They are a bit more lurid, and are more fiercely held. The picture they convey is recognisable, but with the contrast turned up and the voice-over shouted.
In the mind of a true fanatic, the main difference to be found is that the whole conception of means and ends is very different. In the minds of terrorists, opinions and identities part company from interests, which are no longer considered in the same way. Such minds strongly believe that they are acting from consideration of wider interests, and not merely their own. This denial is at the root of terrorist behaviour. The noble cause terrorists adopt allows the demonization of others coupled with the sanctification of self. A life of deprivation, even one’s own death, become worthy things. Everyone else is on a lower plane, less important, and hence disposable.
All of this, worryingly, is not so far from what we all believe about much less important things.