Mainly through better advancement in technology and our understanding of engineering. What with us going from living in caves to making wooden homes to now living in steel and concrete.
I am pretty sure it is tobacco
Constants are kept the same in experiments :)
One of his main points is that in the future, people would be too attached to technology and that we need time to think. He was right about the technology, as many people today are too attached to their phones, computers, etc.
