It is amazing how permanent our civilisation looks to the untrained eye. A swift glance around shows me towering buildings, harbour spanning bridges and roads, fat, wide and black like the arteries of a smoker. It all looks so solid, you can punch it as hard as you like without any result except broken fingers. Yet without constant maintenance the buildings would crumble, the bridges fall and the roads would resemble, well something close to what they are right now.
As we build more and more there is a commensurate rise in the amount of maintenance required to keep it all humming. Of course there is some rationalisation, old buildings and infrastructure are torn down and replaced with fresh and the maintenance assets can be reallocated accordingly. Indeed one of the main reasons for replacing old infrastructure is not because it has ceased to function but simply because the upkeep is getting too expensive. Since we continually build more, build bigger and build more sophisticated there must surely come a day when all of our resources are dedicated to patching up what we already have and there will be simply no capacity for new construction of any kind. We will become a race of squatters inhabiting the decaying monuments of our ancestors expending all of our efforts in a desperate attempt to stop the roof from falling in. Of course one day the decay will outrun our efforts to prevent it and then civilisation will crumble around us.
Once those structures are gone we won't be able to build new ones. Knowledge is like every other skill. If you don't use it, you lose it. Over the past few thousand years we have lost an incredible amount of knowledge as the applications for it became less and less relevant. In Britain some years ago a group of rail enthusiasts built themselves a steam engine. They were able to do this because one of their number, by sheer coincidence, found a copy of the original blueprints. If they hadn't made that discovery they wouldn't have been able to do it because nobody in Britain knows how to build a steam train engine from scratch anymore. It has been less than a hundred years since steam trains were the very symbol of modern civilisation and yet now we would be more successful in reconstructing a dinosaur skeleton. There is nothing really wrong with losing such knowledge because, of course, the steam trains have been replaced with more efficient substitutes. As long as we continue to do that we'll be all right.
But we won't continue to do that. The problem will arise when, after a few generations of doing nothing but maintain and repair existing infrastructure, we are called upon to build replacements. We won't be able to do it. Nobody will know how. We will become like the Mayans, hiding in the jungle hunting with spears a few miles away from a crumbling supercity that their ancestors built. The Mayans didn't suddenly become stupid, they just stopped building cities for a while and suddenly they were running through the jungle trying to avoid Mel Gibson. Rust and cobwebs gather about our civilisation and it is obvious that the human race is doomed.
Wait a minute! Of course; its so simple. Robots! We don't need to spend all that effort maintaining our civilisation. We'll just design robots to do all that for us. Then we can concentrate all our efforts on raising our civilisation to greater and greater heights. Hear me ye Gods, for the human race is rising and we shall challenge for your unapproachable throne. Our time of glory is coming and none shall equal our might and power. We shall gaze down from the pinnacles of our triumph and laugh at the scurrying ants beneath our feet.
Until of course we have to spend all our time maintaining the robots. Then we really will be doomed.