Supersymmetry has beautiful mathematics, and so the professional literature is full of it. As we experienced earlier, for instance when the Yang–Mills theory was proposed, we have a brilliant mathematical scheme, which we do not yet know how to fit into the system of existing laws of Nature. It does not make sense, as yet, but we may hope that it will do some time in the future.

There is another scenario, actually much more appealing to our imagination. We have seen that atoms consist of smaller constituents, the protons, neutrons and electrons. And then we discovered that these constituents, in tum, have a further substructure: they are built from quarks and gluons. Why, as you might already have thought earlier, do not things go on like that? Perhaps these quarks and gluons, and also the electrons and all other particles still called ‘elementary’ in the Standard Model, are in tum built out of yet smaller grains of matter?

You would not be the first to have this idea. I have already reported how Jonathan Swift pictured the world of the small as a carbon copy of the world of larger things. Big fleas carry little fleas on their skins, and so on, ad infinitum. Well, just as biologists would try to explain to you that the kingdom of the fleas has to be looked upon somewhat differently, I must also state that the picture of an infinite repetition of building blocks cannot be correct as such.