There are two distinct views on the meaning of
time. One view is that time is linear and part of the fundamental structure of the
universe, a
dimension in which events occur in
sequence, and time itself is something that can be measured. This is the
realist's view, to which
Sir Isaac Newton subscribed.
[1]
A contrasting view is that time is part of the fundamental intellectual structure (together with
space and
number) within which we sequence events,
quantify the duration of events and the intervals between them, and compare the
motions of objects. In this view, time does not refer to any kind of entity that "flows", that objects "move through", or that is a "container" for events. This view is in the tradition of
Gottfried Leibniz[2] and
Immanuel Kant,
[3][4] in which time, rather than being an objective thing to be measured, is part of the
mental measuring system. The question, perhaps overly simplified and allowing for no middle ground, is thus: is time a "real thing" that is "all around us", or is it nothing more than a way of speaking about and measuring events?
In
physics, time and space are considered fundamental (i.e. they cannot be defined in other terms). Thus the only definition possible is an
operational one in which time is defined by the process of
measurement and by the
units chosen. Periodic events and periodic motion have long served as standards for units of time. Examples are the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, heartbeats, etc. Currently, the unit of time interval (the
second) is defined as a certain number of hyperfine transitions in Cesium atoms (see below). All properties of time follow from this definition.
Time has long been a major subject of
science,
philosophy, and
art. Its measurement has occupied scientists and
technologists, and was a prime motivation in
astronomy. Time is also of significant social importance, having economic value ("
time is money") as well as personal value, due to an
awareness of the limited time in each day and in human lifespans.
Time is a notion that humans created to define a duration ...Duration exist but time doesnt ... The 6 days ur talkin abt abousoun r a duration ... how "much" TIME it took God to create the world ... So we'r talkin about duration in here .. that we can mesure with time ...