102,819
edits
Changes
Created page with 'File:lighterstill.jpgright|frame The '''past''' is contrasted with the present. It is also regarded as the conglomerate of events that...'
[[File:lighterstill.jpg]][[File:Pastpresentfuture.jpg|right|frame]]
The '''past''' is contrasted with the [[present]]. It is also regarded as the conglomerate of [[events]] that happened in a certain point in [[time]], within the [[Space-time]] [[continuum]]. The aforementioned conception is closely related to [[Albert Einstein]]'s [[theory]] of [[relativity]]. The past is the object of [[study]] in such fields as [[history]], [[archaeology]], archaeoastronomy, chronology, [[geology]], (historical geology), historical [[linguistics]], [[law]], paleontology, paleobotany, paleoethnobotany, palaeogeography, paleoclimatology, and [[cosmology]].
[[Humans]] have recorded the past since ancient times, and to some extent, one of the defining characteristics of [[human being]]s is that they are able to record the past, recall it, [[remember]] it and confront it with the current [[state]] of affairs, thus enabling them to plan accordingly for the [[future]], and to theorise about it as well.
==Philosophy and science==
According to [http://en.wikipedia.org/wiki/Presentism_(philosophy_of_time) presentism], the past does not strictly exist; however, the [[methods]] of all [[The Sciences|sciences]] study the world's past, through the [[process]] of evaluating [[evidence]]. Presentism is compatible with Galilean relativity, in which time is independent of space but is probably incompatible with Lorentzian/Einsteinian relativity in conjunction with certain other philosophical theses which many find uncontroversial.
In [http://en.wikipedia.org/wiki/Classical_physics classical physics] the past is just a half of the [[timeline]]. In [http://en.wikipedia.org/wiki/Special_relativity special relativity] the past is considered as [[absolute]] past or the past cone. In [[Earth]]'s scale the [[difference]] between "classical" and "relativist" past is less than 0.05 s, so it can be neglected in most cases.
In the modern [[theory]] of [[relativity]], the conceptual [[observer]] is at a geometric point in both [[space and time]] at the apex of the 'light cone' which observes [[events]] laid out in time as well as space. Different observers can disagree on whether two events at different locations occurred simultaneously depending if the observers are in relative [[motion]] (see [http://en.wikipedia.org/wiki/Relativity_of_simultaneity relativity] of [[simultaneity]]). This theory depends upon the idea of time as an extended [[thing]] and has been confirmed by [[experiment]] and has given rise to a philosophical viewpoint known as [http://en.wikipedia.org/wiki/Four_dimensionalism four dimensionalism]. However, although the [[contents]] of an observation are time-extended, the conceptual observer, being a geometric point at the [[origin]] of the light cone, is not extended in time or space. This [[analysis]] contains a [[paradox]] in which the conceptual observer contains nothing, even though any real observer would need to be the extended contents of an observation to exist. This paradox is partially resolved in [[Relativity]] theory by defining a '[[frame of reference]]' to [[encompass]] the measuring instruments used by an observer. This reduces the time separation between instruments to a set of constant intervals.[2]
==References==
# Hegeler, E. C., & Carus, P. (1890). The Monist. La Salle, Ill. [etc.]: Published by Open Court for the Hegeler Institute. page 443.
# Petkov 2005
[[Category: Physics]]
[[Category: Philosophy]]
The '''past''' is contrasted with the [[present]]. It is also regarded as the conglomerate of [[events]] that happened in a certain point in [[time]], within the [[Space-time]] [[continuum]]. The aforementioned conception is closely related to [[Albert Einstein]]'s [[theory]] of [[relativity]]. The past is the object of [[study]] in such fields as [[history]], [[archaeology]], archaeoastronomy, chronology, [[geology]], (historical geology), historical [[linguistics]], [[law]], paleontology, paleobotany, paleoethnobotany, palaeogeography, paleoclimatology, and [[cosmology]].
[[Humans]] have recorded the past since ancient times, and to some extent, one of the defining characteristics of [[human being]]s is that they are able to record the past, recall it, [[remember]] it and confront it with the current [[state]] of affairs, thus enabling them to plan accordingly for the [[future]], and to theorise about it as well.
==Philosophy and science==
According to [http://en.wikipedia.org/wiki/Presentism_(philosophy_of_time) presentism], the past does not strictly exist; however, the [[methods]] of all [[The Sciences|sciences]] study the world's past, through the [[process]] of evaluating [[evidence]]. Presentism is compatible with Galilean relativity, in which time is independent of space but is probably incompatible with Lorentzian/Einsteinian relativity in conjunction with certain other philosophical theses which many find uncontroversial.
In [http://en.wikipedia.org/wiki/Classical_physics classical physics] the past is just a half of the [[timeline]]. In [http://en.wikipedia.org/wiki/Special_relativity special relativity] the past is considered as [[absolute]] past or the past cone. In [[Earth]]'s scale the [[difference]] between "classical" and "relativist" past is less than 0.05 s, so it can be neglected in most cases.
In the modern [[theory]] of [[relativity]], the conceptual [[observer]] is at a geometric point in both [[space and time]] at the apex of the 'light cone' which observes [[events]] laid out in time as well as space. Different observers can disagree on whether two events at different locations occurred simultaneously depending if the observers are in relative [[motion]] (see [http://en.wikipedia.org/wiki/Relativity_of_simultaneity relativity] of [[simultaneity]]). This theory depends upon the idea of time as an extended [[thing]] and has been confirmed by [[experiment]] and has given rise to a philosophical viewpoint known as [http://en.wikipedia.org/wiki/Four_dimensionalism four dimensionalism]. However, although the [[contents]] of an observation are time-extended, the conceptual observer, being a geometric point at the [[origin]] of the light cone, is not extended in time or space. This [[analysis]] contains a [[paradox]] in which the conceptual observer contains nothing, even though any real observer would need to be the extended contents of an observation to exist. This paradox is partially resolved in [[Relativity]] theory by defining a '[[frame of reference]]' to [[encompass]] the measuring instruments used by an observer. This reduces the time separation between instruments to a set of constant intervals.[2]
==References==
# Hegeler, E. C., & Carus, P. (1890). The Monist. La Salle, Ill. [etc.]: Published by Open Court for the Hegeler Institute. page 443.
# Petkov 2005
[[Category: Physics]]
[[Category: Philosophy]]