The extent to which ancient humans studied time is uncertain because they had no well developed language. Nonetheless, we know that they expressed the passing of time in cave art and in several of their rituals, especially birth and death rituals. The continuity of time and the partition of time implied in their art and rituals, indicate that their concept of time was not limited to the mundaneness of time measurement. The rituals of ancient Africa, still practised in some parts of modern Africa, are rich in references to the longness of time, the twirling of time, the newness of time and the transition in time. The great pyramids commissioned by the Pharoahs of ancient Egypt and built by ancient Egyptians, were partly if not wholly, inspired by their concept of Time. Ancient Babylonians and ancient Indians and Chinese studied Time abstractly in their astrology, and ancient Hebrews made many references to time in their songs and poems. The following is one of such poems:
To every thing there is a season, and a time to every purpose under the heaven: A time to be born, and a time to die; a time to plant, and a time to pluck up that which is planted; A time to kill, and a time to heal; a time to break down and a time to build up; A time to weep, and a time to laugh; a time to mourn, and a time to dance; A time to cast away stones, and a time to gather stones together; a time to embrace, and a time to refrain from embracing; A time to get, and a time to lose; a time to keep, and a time to cast away; A time to rend, and a time to sew; a time to keep silence, and a time to speak; A time to love, and a time to hate; a time of war, and a time of peace. Ecclesiastes 3:1-8 (KJV).
But it was in ancient Greece that a new curiosity about the concept of time began. The ancient Greeks (also ancient Romans) were uniquely adept in investigating ideas from other civilizations, particularly the African and Meditteranean civilizations, refining the ideas through the faculty of thought, and in many instances re-inventing and extending the ideas. This ancient Greco-Roman trait detached time from rituals, songs, poems and measurement, and made it a subject of pure thought. Consequently, various intellectual abstractions of time> began to emerge.
In the 5th century B.C., Plato described time as the moving image of eternity. In the 4th century B.C., Aristotle described time as the number or measure of motion. Plotinus (a.d.205-70), a Roman philosopher and founder of Neoplatonism ( the school of thought that sought to develop and synthesize the metaphysical ideas of Plato), metaphysically described time as the productive life of the soul. These thinkers and several others in the ancient cities of Rome, Alexandria in Egypt, Hippo in Carthage, and Athens in Greece, invigorated the debate on the nature of time. Today, the nature of time remains a very much debated concept. Despite being one of the most successfully measured quantities, it remains the most difficult to conceptually pin-down. The great theologian, St Aurelius Augustine eloquently indicated in The Confession, that the understanding of Time is no easy matter. He wrote:
"For what is time? Who could find any quick or easy answer to it Who could even grasp it in his thought clearly enough to put the matter into words? Yet is there anything to which we refer in conversation with more familiarity, any matter of more common experience than time? And we know perfectly well what we mean when we speak of it, and understand just as well when we hear someone else refer to it. What, then, is time? If no one asks me, I know; if I want to explain it to someone who asks me, I do not know. I can state with confidence, however, that this much I do know: if nothing passed away there would be no past time; if there was nothing still on its way there would be no future time; and if nothing existed, there would be no present."
No wonder there are numerous definitions of time. Definitions range from ordinary to profound, and from brief to lengthy. But a serious exposition of time must go beyond definition and provide in depth analysis for its position. The links at the end of this presentation refer to insightful expositions on the subject of time by several distinguished thinkers. The following are some selected definitions of time:
"Time present and time past are both perhaps present in time future And time future contained in time past." T.S. Eliot, Four Quartets
Tomorrow, and tomorrow, and tomorrow creeps in this petty pace from day to day To the last syllable of recorded time, And all our yesterdays have lighted fools The way to dusty death." William Shakespeare; Macbeth V:5
"Regarding the origin of life: Time performs the miracles. Time is infact the hero of the plot" George Wald
"Time is what happens when nothing else does." Richard P. Feyman
"The great thing about time is that it goes on." Benard D'Espagnat
"Know the silent time, and let the silent time know you." Margaret O. Simate
"Time is nature's way to keep everything from happening at once. Time is clothed in a different garment for each role it plays in our thinking. The word time came not from heaven but from the mouth of man." John Wheeler
"Time is the mediator between the possible and the actual." G.J. Whitrow
"Clock time is our bank manager, tax collector, police inspector; This inner time is our wife." J.B. Priestley
"No one, apparently can claim to know what time is. Nevertheless, there is this brave breed of people called physicists who used this elusive notion as one of the basic building blocks of their theory, and miraculously, the theory worked. When one of the leading figures of the clan, by the name of Albert Eistein, quietly mumbled his secret incantation which sounded like "combine time with space in such a way that nothing can travel faster than the speed of light, then mass is equal to energy," lo and behold, atoms exploded ever so noisily." Masanao Toda
"There is no doubt that physicists succeeded in trapping some really important ingredient of time within their capsule labeled t, but equally certain it is not all of the time that is captured within their capsule. Our intuition is crying out to tell us that time is something that flows unlike the physical time which is frozen still." Masanao Toda
"They say more people are laid low by time anxiety than by time itself. But only time is fatal;" Martin Amis
"All change, and time's arrow, point in the direction of corruption. The experience of time is the gearing of the electrochemical processes in our brains to this purposeless drift into chaos as we sink into equilibrium and the grave." Peter Atkins
"Time like an ever-rolling stream, bears all its sons away." Isaac Watts
"Time travels in divers places with divers persons. I'll tell you who time ambles withal, who time trots withal, who time gallops withal, and who he stands still withal." William Shakespeare
"When I close my eyes and retreat into my inner mind, I feel myself enduring, I do not feel myself extensive. It is this feeling of time as affecting ourselves and not merely as existing in the relations of external events which is so peculiarly characteristic of it; space on the other hand is always appreciated as something external." Arthur Eddington
"It seems to me that there are several discrepancies between what we consciously feel, concerning the flow of time, and what our (marvellously accurate) theories assert about the reality of the physical world. These discrepancies must surely be telling us something deep about the physics that presumably must actually underlie our conscious perceptions" Roger Penrose
"Our perception of time clearly has something to do with our brain processes. If our brains worked at twice their actual speed, then one second would seem the way two seconds does to us now." Paul Davies
"Because mathematicians frequently make use of Time, they ought to have a distinct idea of the meaning of that word, otherwise they are Quarks" Isaac Barrow
"Scientists have been too occupied with the development of new theories that describe what the universe is to ask the question why? On the other hand, the people whose business it is to ask the question why?, the philosophers, have not been able to keep up with scientific theories... However, if we do discover a complete theory, it should be understandable by everyone, not just a few scientists. Then we shall, philosophers, scientists, and ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist." Stephen Hawkins.
Peter Oye Sagay