Imagine the inside of St. Peter’s in Rome filled with a huge quantity of fibers around a millimeter in diameter that crisscross the building in every… - Valentino Braitenberg

It is actually impossible in theory to determine exactly what the hidden mechanism is without opening the box, since there are always many different mechanisms with identical behavior. Quite apart from this, analysis is more difficult than invention in the sense in which, generally, induction takes more time to perform than deduction: in induction one has to search for the way, whereas in deduction one follows a straightforward path.

We will talk only about machines with very simple internal structures, too simple in fact to be interesting from the point of view of mechanical or electrical engineering. Interest arises, rather, when we look at these machines or vehicles as if they were animals, in a natural environment. We will be tempted, then, to use psychological language in describing their behavior. And yet we know very well that there is nothing in these vehicles that we have not put there ourselves.

Ad Aertsen succeeds in allowing his sense of humour to shine through the deep seriousness of his scientific ethos. He also has a very balanced attitude to the question of "theory or experiment".