The most important thing about the world today is that it is in the middle of a short transition from all of past human history to a new and different future history. We can't know most things about the future, but we can have reasonable confidence about some important features of the coming modern world.
After the current transition is completed, mostly by the end of next century, almost all people will live long, healthy, comfortable lives, protected from nature. They will work with their minds or their fingers in a global commercial economy concerned more about ideas, information and relationships than about things.
This will be a sharp departure from the past. Virtually all past civilizations were made up of the few who were skimming a share of the output of large numbers of poor and powerless people.
The life expectancy, diet, living conditions and character of work of the great majority of people in the world in 1800 were not very different than those of ordinary people throughout all time, back to the ages of hunter-gatherers. Life expectancy throughout that time was always not much less than 30 years.
Amidst this transition, no sizeable country will be able to prosper unless almost all of its population is educated and productive. Everywhere the whole people will count, not just the elites. These countries of free people will be built on law and politics and commercial behavior. Violence will not be a significant part of the experience of more than a few people. In other words, the lives of people in the future — and of some people already — will be immensely different than the lives of almost all people in the past.
Today in Western Europe — the only region, apart from North America, composed entirely of modern countries — we see one of the most dramatic effects of the change that will come to the whole world.
No country in Western Europe believes that it needs military force to protect itself from any of its neighbors, nor does any country's military force greatly affect its influence in the region.
If the British fleet sank, Britain would not lose its place in the world. Western Europe is a zone of peace from which the war system has disappeared.
The end of the war system within Western Europe didn't happen because Europeans are wiser or more moral or less aggressive than before. Human nature hasn't changed, and Europeans pursue and use power as much as ever. The war system disappeared because modern countries are different than traditional countries — and therefore they behave differently. These differences are going to make a new history which is distinctly different from the history we know.
One of the main things that we can't know about the future world is how many people will live in it. We can be confident that the world population will begin to become smaller sometime in the middle of this century (after growing perhaps 15% larger than it is today).
But we can't know whether the number of people will continue becoming smaller each year for 50 years or 500 years. It all depends on how many children our grandchildren and their grandchildren on into the future decide to have.
All over the world, not just in Europe and China and Japan, each new generation of women has been having fewer children, and there is almost no country — other than the United States and Israel — where the decline stopped at 2.1, the number needed to prevent the population from eventually falling (in the absence of immigration).
In a few centuries, the world population could fall back to a billion people, where it was at the beginning of the last century. Or peoples' values could change so that they decide on average to have more than 2.1 children for each woman. Then the world population would again start to rise until eventually there are many more people than now.
More important, we can't know whether the world of the future will be a "better world." While the wealth, freedom and peace we can expect will be a great triumph, they are not everything. We can't know whether people will be happy or good. Perhaps the biggest challenge we will have to face in the coming future world is to find a substitute for the adversity that has helped to shape human character in the past.