The 20th Century was a period in which the population quadrupled in 100 years. I would like to do the following experiment to show you how abnormal this is. Let us think how long it would take the population increasing by fourfold every century to reach the same weight as the mass of Earth. You may think a fourfold increase over a century is not much of an increase, but actually, it only takes two thousand and several hundred years for the weight of human beings to reach the mass of Earth. It means that our weight would reach the mass of Earth in a much shorter period of time than our history of creating and living in the homo-sphere. However, this simply will not happen. This will not happen because we are now living by renting a part of matter in this planet we call Earth. However, this is the result of a simple calculation based on the increase rate in the previous century. Furthermore, 60 to 70 percent of our body is water. So there's no use in comparing our weight with the entire planet Earth. We should be comparing it with the mass of the ocean because that's where the largest quantity of water exists on Earth's surface. When population quadruples every 100 years, Earth's population will reach the mass of the ocean in only 1,500 to 1,600 years.

　

If you compare the increase rate of human mass with the speed of Earth being formed some 4.6 billion years ago in the Solar System. It is more than 10,000 times faster. In terms of flow of energy and matter in planet Earth, you can say that we are creating and living in homo-sphere by moving matter at the speed more than 10,000 times faster than the flux of energy and matter.

　

We talk in scales of time such as 1 year and 100 years. But in this case, we are now living on this Earth by accelerating Earth's physical flow by about 10,000 times to create the homo-sphere.

　

In this context, you will see that our notion of 1 year or 100 years has tremendous significance when seen in scale of the whole Earth. The history of creating civilization and homo-sphere over a period of 10,000 years corresponds to 100 million years when seen in time scale of movement of physical matter on Earth. While many components of the Earth system exist today as a result of branching of material sphere throughout Earth's history, this means that homo-sphere emerged on Earth in the same manner as oceans and continental crust were born. Having this awareness will give us a better understanding of the significance of our decisions about the future is actually determining our future including that of the planet Earth.

　

So you can say that our ideas about what we are going to do in the future will determine our future in the next hundred years. There is nothing we can do about it unless we have some clear idea about "what we are going to do". When I say "there's nothing we can do about it", it means, for example, that we are going to collapse if we think about the 21st Century based on the concepts and systems that we obtained under such boundary conditions of the homo-sphere. Dreadful future lies ahead unless we design the homo-sphere of the 21st Century based on a completely different way of thinking. In my view, thinking about these matters is in fact what it really means to think about the future of human society and the population problem.

　

In conclusion, I would like to say a few words about how we should think about our future. What do we do when we think about the future? We analyse history. which consists of various things that occurred in the past, and extend it in terms of time to think about the future. That is why we cannot think about the future unless we understand what happened in the past. From the viewpoint of homo-sphere-based mindset, it is not possible to think about the future of civilization if we approached history from such short time span. As I mentioned earlier, civilization is a way of life based on creation of homo-sphere. It is therefore meaningless unless history is at the level in which homo-sphere is discussed as its component.

　

It means that, in order to have a discussion about whether homo-sphere is a stable existence in the Earth system, we must talk in the time scale of how this component was born and what would happen to it. We also need to discuss in the time scale of what the components other than homo-sphere were like. It means that we cannot discuss the future of homo-sphere unless we understand history in the same time scale as the history of Earth and the history of universe.

　

That is why we cannot discuss the future of homo-sphere for the next 100 years based on the mere history of civilization; I think it is necessary for us to engage in discussion about how we should live from now based on − and from the viewpoint of − 15 billion years of history of universe, 4.6 billion years of history of Earth or 3.8 billion years of history of life on the planet.

　

What is history when you look at it in time scale of 15 billion and 4.6 billion years? In a word, it means "differentiation", which means to divide and transform. Matter is differentiated. The same term is also used in biology. You talk about "differentiation of species". The term "differentiation" is commonly used in natural science. Actually, the direction of history is basically determined based on the concept of "differentiation".

　

Big Bang, the beginning of the universe, was a completely homogeneous state. There was no differentiation. There was no distinction between energy and matter. Varieties of matters were also very simple. There were particles of a type that fell under the category of ultimate component. They were differentiated in various ways to create a wide range of matters in the universe today. This is differentiation. The same can be said about Earth. It was in the form of a fireball when it was born and was made up of an ocean of magma and primordial atmosphere, which was a volatile element surrounding it. This turned into Earth we have today which is divided into various material sphere such as atmosphere, ocean and earth crust, which, in turn, is divided into continental crust and oceanic crust, with mantle underneath them, and mantle is divided into upper mantle and lower mantle. The core, which is a mass of iron-nickel alloy, is further divided into the outer core and the inner core. Diversification continued as organisms were born in it and created the biosphere, and as we were born in it and created the homo-sphere.

　

It is considered that only one kind of life, one kind of cell was born on Earth at the beginning. Numerous varieties of life, probably in the tens of millions, were born on Earth from this single life. This is also diversification.

　

For this reason, the basic understanding is that history is a differentiation process. Then arises the question "Why did nature diversify?" This is also a very simple matter; Diversification of the universe, diversification of Earth and diversification of life all occurred as a result of cooling. The history of diversification is the outcome of cooling of the universe, cooling of Earth and cooling of the global environment.

　

That is why we must think about the meaning of differentiation in homo-sphere, or the meaning of the cooling of homo-sphere, when we think about the internal system of homo-sphere, assuming that homo-sphere will stabilise inside the global system. This corresponds to the discussion of what the internal structure of homo-sphere is going to be like and what kind of units it would actually be comprised of.

　

What we will need to do from now on is not to rely on the single mode of life we call "civilization". I think that the true meaning of "differentiation of homo-sphere" based on the history of universe and life on Earth lies in discussing how we should go about creating the internal system of a new homo-sphere on top of what we have been referring to as "civilization", − the way of life that have been fostered under various regions and climates.

　

The kind of unit that we are going to create as the internal structure or internal system of homo-sphere is a very important issue when we think about the future of homo-sphere. I think such discussions are taking place in various places, although they may not necessarily be coming from the idea I mentioned here today.

　

When we think about the future of human society − or to use my expression "the future of homo-sphere" − at the beginning of the 21st Century, I think we would not be able to come up with a good directionality unless we take a bird's eye view and see or grasp the problem from the viewpoint of the universe and Earth.

　

Thank you.