Throughout the history of mankind, people have been trying to understand how the world in which they happened to exist works.
In the current historical period, the most authoritative and popular way of observing and explaining the phenomena of the surrounding reality is the scientific method of cognition.
The main problems that worry people both several thousand years ago and at the moment can be reduced to several simple and understandable questions: “Who are we?”, “Why and how did we arise?”, “Why do we exist?” and “What is space and time within which our existence takes place?” In this article we will look at the question of what time is.
History of the concept of “time”
For a long time, people have noticed that events occurring in the world happen in a certain order and obey some internal logic: what happens earlier has an irreversible effect on what happens later – just as a hatched chick cannot climb back into the egg, so one cannot go back to yesterday, or even to the second that has just passed.
These features of the surrounding world are reflected many times in a long series of folk proverbs and sayings: “You cannot turn back the past,” “You cannot enter the same river twice,” and so on. It was this sequence of events that people began to call time.
The concept of time in physics
Since scientific knowledge was divided into independent, albeit interconnected, branches, the concept of time has been included in the field of research in which science called physics is engaged. Almost every reader of this article knows physics at least as a school subject, but the field of physics research is by no means limited to the framework of the school curriculum. Among other things, the tasks of physics include the search and formulation of a clear and reliable answer to one of the so-called “eternal questions”: “What is time?”
It should be immediately reported that an unambiguous and indisputable answer to this rather simple sounding question has not yet been obtained, although the best minds of mankind are trying to do this by all means available to them. Nevertheless, we can somewhat reassure the reader by informing him that scientists have managed to develop several fairly convincing theories describing the role of time in the processes that occur around and within us.
From the point of view of physics, time is one of the dimensions. Some physical quantities are called measurements, such as length, width, height and, as we have already mentioned, time. Other physical quantities, such as speed, temperature, humidity, etc., are, as it were, secondary to those listed above or derived from them. Length, width and height differ from other physical quantities in that they describe not the properties of material objects, but the space in which these objects are located and move.
We can say that physical objects themselves do not have length, width and height – they simply coincide with the height, length and width of the space that they occupy at a given moment in time. Therefore, length, width, height and time are called measurements and endowed with a certain primacy in relation to other physical quantities.
It is quite simple to understand this, because if an object does not have a position in space and time, then it simply does not exist in the reality around us, and as a result cannot have any physical characteristics.
Together with spatial dimensions, time constitutes the so-called space-time continuum, which includes all the objects and events we observe. We ourselves are also in the space-time continuum, moreover, from a scientific point of view, we are just a part of it and cannot exist separately from it.
The very existence of the space-time continuum can be considered quite obvious, because even if we only dream about the environment, then the action of our dreams takes place in time and space. But about the essence and form of this continuum, it is possible to conduct debates that have not subsided since the existence of science; one might even say that it was these disputes that led to the emergence of science as such.
Four-dimensional space and eternalism
There is a hypothesis according to which time can be considered as the fourth spatial dimension, which essentially does not differ from length, width and height. From this point of view, events do not actually occur in a certain order, this order arises only due to the peculiarities of our perception. In philosophy, this approach is called eternalism.
From the point of view of eternalism, material objects, including people and animals, do not move in time at all, since no movement in time is possible in principle. Eternalism views the past and the future as objectively existing states of reality, the same as the present moment.
This approach does not explain why we perceive events exactly in the sequence in which we perceive them, but in fairness it should be noted that the traditional approach to space-time also does not give a convincing and comprehensive answer to this question, which is why the question of the essence time is usually referred to the category of “eternal”.