Phenomena such as memory, experience, observation, anticipation, and hope are all essential for the way time is understood
Many philosophical and religious schools have assumed that no beginning or end can be attributed to time. For instance, in Indian thought the universe is largely conceived as undergoing repeated creation and dissolution. According to this cosmological model, each world-cycle has to be measured in terms of billions of humans’ years. Ancient Greek thought includes the even stronger idea of cyclic time according to which not only the cosmological processes but also all individual destinies are repeated in every detail in time. Jewish, Christian, and Muslim philosophers have had to reject this idea of cyclic time because it leaves no room for genuine progress or final salvation.
Some Muslim thinkers such as Al-Farabi and Avicenna held that the act of creation should be conceived as atemporal and purely logical. In Judaism and Christianity, however, most philosophers have rejected this view maintaining that God’s creation of the world was in fact its temporal beginning. In Judaic thought some have argued that time existed and the Torah was created before the creation of the world. This view of time would allow the notion of the universe being created in time. However, according to the most common view in traditional medieval philosophy, time is considered to be relational; that is, there can only be time in relation to a world of events. With this view of time, means that the universe does not owe its existence to anything in the physical world, and it can only be explained by reference to something that is not a part of this temporal world. The idea of the absolute beginning of the universe does not imply any change from one state to another.
Furthermore, since the being of what is eternal does not pass away, eternity is present in its essentiality to any time or instant of time. We may see an example of sorts in the case of a circle. Although it is indivisible, it does not co-exist simultaneously with any other point as to position, since it is the order of position that produces the continuity of the circumference. On the other hand, the center of the circle, which is no part of the circumference, is directly opposed to any given determinate point on the circumference. Hence, whatever is found in any part of time coexists with what is eternal as being present to it, although with respect to some other time it be past or future.
Since antiquity two images of time have been discussed: the line made up of stationary points and the flow of a river. Philosophically speaking, these images correspond to two positions: ‘being as timeless’ and ‘being as temporal.’ The two positions can be found in early Indian thought, for instance, as held in Brahmanism and Buddhism, respectively. The different schools in the Brahmanical tradition have maintained that the ultimate being is timeless (i.e., uncaused, indestructible, beginning less, and endless). Buddhists, on the other hand, have claimed that being is instantaneous and that duration is a fiction since according to their view a thing cannot remain identical at two different instants.
In classical Greek thought the tension between the dynamic and the static view of time has been expressed, for example, by the Aristotelian idea of time as the number of motion with respect to earlier and later, an idea that comprises both pictures. On the one hand time is linked to motion (i.e., changes in the world), and on the other hand time can be conceived as a stationary order of events represented by numbers. This discussion is also reflected in Isaac Newton’s ideas of time, according to which absolute time ‘flows equably without relation to anything external.’ The basic set of concepts for the dynamic understandings of time arepast, present, and future. Philosophers discuss intensively which of the two conceptions is the more fundamental for the philosophical description of time.
Most writers in philosophy defend the view that ‘my Now,’ ‘my present choice,’ or ‘my present awareness’ actually represents something real. They normally find it obvious that the concept of time has to be related to the human mind. Therefore it becomes more natural to describe time by means of tenses (past, present, and future) than by means of instants (dates, clock-time, etc.). With tenses, one can express that the past is forever lost and the future is not yet here. Without these ideas one cannot hope to grasp the idea of the passing of time. Phenomena such as memory, experience, observation, anticipation, and hope are all essential for the way time is understood. Notions of past and future time, the interpretation of the past, and expectations of the future are all interwoven in the human mind. Nevertheless, some scholars claim that the distinction between past and future is objective, or at least inter-subjective.
In order to gain more knowledge about the temporal aspects of reality, time has to be studied within many different strands of science. If such studies are to lead to a deeper understanding of time itself, various disciplines have to be brought together in the hope that their findings may form a new synthesis, even though one should not expect any ultimate answer regarding the question of the nature of time. If a synthesis is to succeed, a common language for the discussion of time has to be established.