1.
S₁: Human ways of life have steadily changed.
S₆: During the last few years change has been even more rapid than usual.

P: From that time to this, civilisation has always been changing.
Q: About ten thousand years ago, man lived entirely by hunting.
R: Ancient Egypt -Greece - the Roman Empire - the Dark Ages and the Middle Ages - the Renaissance the age of modem science and of modern nations - one has succeeded the other; and history has never stood still.
S: A settled, civilised life began only when agriculture was discovered.