On a philosophical note, there are two world views on time: linear time, a product of Christianity and cyclical time, a prechristian/pagan concept. Linear time assumes progress of sorts over time. The cyclical time concept holds that there is little actual progress, everything is a cycle as in the seasons of the year, human lifespans, history repeats itself.
I am thinking that perhaps time has both a cyclical and a linear component. For linear: Life today is much different than 100 AD, for example. Technological development certainly seems to be following a linear path. For cyclical: Early human civilization seems to have been cyclical with little real change for thousands of years. Cyclical years, cycles of plenty, famine, wars, rise and fall of empires all have cyclical features.
What I have been wondering is, perhaps time is linear with cycles along the path, or perhaps we are actually in a cycle currently, that this present but relatively short period of affluence is actually one large cycle of plenty and famine but being imbedded in it, we cannot tell we are in a cycle any more than a beetle can tell the earth is round by walking on its surface. The American empire, for example appears to be following a pattern similar to that of the Romans and British. I'd love to hear anyone's thoughts on this.