Time is not a string but a blanket...a really, really thick blanket
Time is not a string
There is a common belief, perpetrated by monotone history teachers across the world, that time can be represented by a string. As we progress down the string, we view history; as we progress up the string, we view the future. Want to view a point in history? Just scan down the string until you find the point that you want. Unfortunately (or rather fortunately?), time is much, much more complicated than that.
For one thing, a string is much too simple. A string is reminiscent of those silly timelines in high school that are designed to give nothing more than a title and a date. When did Columbus sail the ocean blue? I bet you can spout off the date, but can you tell me what it would have been like sail across the ocean in 1492? Can you tell me much about maritime movement using sails? How did they sleep or eat? A more thorough look at history is much more encompassing than a simple string or line. It is much more three-dimensional.
That's not how things work!
Of course, I can't leave that idea without mentioning that there has never been, nor will there ever be, a truly comprehensive history of the world...or a nation...or even of your life. Unfortunately for later readers, any history written has had key points carefully determined before the writing, since we obviously can not write every little thing. Beyond that, different histories have different purposes and different authors writing them for those purposes, so no two history books will be the same.
That's not the only point, though. One historian may view military conquests as key to understanding the past, while another may view trade relations or leadership as important. Over the last fifty years, what is important to most scholars has changed drastically, culminating in a desire not to understand the important people but the common people.
Yeah, a blanket
If we want to understand the little people, we need to first understand the broader picture. Here comes the blanket. A single string may represent a single person's life (though even one life is probably too much for a single string), but as we start to put these strings together, a pattern begins to emerge on the surface. You see, all of those people in a single family tend to form their own little cultural identity (an image). All of those families in a village tend to form a cultural identity, which is the building blocks of a society. That small village is then a part of a larger community, which may be a part of a state or nation which is in turn a part of a broader geographical location, and each of these little images form a larger image, the largest being what can be called geographical time.
Think about it. Rivers, valleys, oceans, and more—all of these may form borders or roads or farmland or whatever. Mountainous regions gave way to mining operations, but not necessarily to farming, so trade began between those who had and those who had other things. Even today, steel and coal in America is found in certain areas, and other areas give way to the production of cereals or the breeding of livestock. From lobsters to oil, textiles to grapes, geography plays an important part in our nation's life.
Because of the location, our society has formed an image different from any that one might find in Europe or other "Western" nations, and the same is true about any European or Asian or African or whatever nation throughout history. These societies formed, creating their own languages and cultures, their own images on the blanket of humanity, and when we look back at these images, we are able to learn so much more about the people who lived and died in those societies.
...but much more than a blanket
Of course, a snapshot of that blanket only represents a point in time, and as time progressed, the images changed from layer to layer. Sometimes a new cultural idea was introduced to a society, and therefore the image of one begins to look more like that of the other, though still a completely different image. From the earliest of human times up until now, this rather thick patch quilt has morphed into what we now live. Because of these synchronic layers diachronically placed, historians and archaeologists are able to learn not only what happened way back when but how we got to the point in which we now stand—which is necessarily on the shoulders of those who came before.
Unfortunately for us, humans tend to be so focused on their own little patches on the blanket, that they ignore the broader image. Still further, humans tend to be so focused on the present layer of the quilt that they often ignore the deeper layers and forget where we came from. Thus, the inaccurate though wise adage: history repeats itself, and that often in a negative way. Unless we learn to view the quilt of humanity, I fear that we, just like every generation before us, will learn little and change slowly.