A stage is a period of time delimited and always opposed to a previous moment and a later one. We can talk about different types of stages and while this term can be applied for example to stages of production, stages of life and many other meanings, the most common use for the concept of stage is one that is directly related to history, not only of Humanity but with the history of any phenomenon related or not to the human being.
In all cases, the idea of a stage refers to a situation more or less delimited by a beginning and an end. At the same time, a stage has characteristics that are specific to it and that have to do with what happens, is done or happens in it. Furthermore, a stage always implies the succession of events or phenomena (both human and natural) that have been logically ordered and classified in the understanding of the human being.
If we take the notion of stage as a succession of historical events, we can point out that for the history of Humanity there are various stages. This periodization in moments of greater or lesser duration has been carried out by the human being in order to more easily understand the historical processes that have taken place and that continue to happen day by day. This is why we can mention historical stages such as Prehistory, the Ancient Age, the Middle Ages, the Modern Age and the Contemporary Age. Each of them has specific characteristics that define it and differentiate it from the others. As can be seen, the historical stages are inserted in a linear order that supposes their succession in the face of the wear of their main elements.
Also in this sense we can speak of stages in the existence of the Earth and this is where Geology comes into play, a science that will help us study the development and evolution of natural phenomena since the very creation of the Universe.
