No resource, even one as apparently unlimited as a simple number, is truly infinite.
Cars: When people devised the first petrol engined motor vehicles around 100 years ago, could they have even imagined ‘traffic congestion’? I doubt it. They saw a world of open roads and dreamt of amazing possibilities. And now that we have realised those dreams we find the roads less open than they used to be, and the possibilities somehow less enthralling than we used to suppose. But nonetheless cars do give amazing freedom to travel even if not quite as envisaged by the ‘founding fathers’. And what constrains the perfection of their ubiquity are resources which must at one time have seemed unlimited: the availability of hydrocarbon fuels and roads.
Computers: I have lived through years of breathtaking evolution of computers such that the even the name – implying relevance to calculations – has now become inappropriate. I remember gazing open mouthed when using an early version of Mosaic, I was shown a ‘web page’ hosted in China. Back then the internet was empty and simply ‘being on the internet’ was an achievement worthy of note. But the internet operates on a system of connections between computers called Version 4 of the Internet Protocol (IPv4) in which every computer had a unique number – like a telephone number. At the start they created numbers with the form w.x.y.z. where each letter represented a number between 0 and 255, allowing up to 4.2 billion possible devices to be connected to any other device. When we type in a web address (like http://www.protonsforbreakfast.org) our computer connects to to a special computer (called a name server) that searches for the IP number (called an IP address) connected with that web address. But in the short time of 20 years, every one of those IP addresses has been allocated, and over the next few years we will need to go beyond IPv4 to IPv6 which allows for the possibility to allocate 5×1028 IP addresses to every human being on Earth (surely enough to be going on with?). What struck me about this announcement was they way in which the internet had expanded beyond anyone’s imagination and become limited by what had once seemed a practically unlimited resource: IP addresses.
And that seems to be the way of the future. Its just really difficult for even the most far-sighted of us to see even a decade or two ahead.