B-Theory of time
Encyclopedia
The B-theory of time is a term, given to one of two positions taken by theorists, in the philosophy of time
. The labels, A-theory and B-theory
, are derived from the analysis of time and change developed by Cambridge philosopher J. M. E. McTaggart
in The Unreality of Time
, in which events are ordered via a tensed A-series or a tenseless B-series.
http://hylo.loria.fr/content/papers/files/tense.pdf) take the tensed notions associated with the past, present and future to be the irreducible foundations of temporality and our conceptions of temporal fact, are called A-theorists (or presentists
). A-theorists deny that past, present and future are equally real, and maintain that the future is not fixed and determinate like the past. Those who wish to eliminate all talk of past, present and future in favour of a tenseless ordering of events are called B-theorists. B-theorists (such as D.H. Mellorhttp://people.pwf.cam.ac.uk/dhm11/Tense.html and J.J.C. Smarthttp://docs.google.com/viewer?a=v&q=cache:5sRVGv3QVqEJ:faculty.fullerton.edu/jeelooliu/420_(08)_folder/420_Smart_Tenseless_Theory_of_Time.pdf+jjc+Smart,+time&hl=en&gl=uk&pid=bl&srcid=ADGEESj0Xc_Ysa9-LvI6kx2yVfkGcPkoXK9FEOKyrE4BgwzkDZUX__yFJy2jR-It_lvMGyTka4CsBri4Be0eaCaEtdcpl8zXHBsJ6Kl98DrGrftfuOKqqxJTlXNN7-0ok6WIwbHzSwPj&sig=AHIEtbQQz0Y0XiRU3vXT65BXOgavfEy_Ww) believe that the past the present and the future are equally real.
The past, the present and the future feature vary differently in deliberation and reflection. We remember the past and anticipate the future, for example, but not vice versa. B-theorists maintain that the fact that we know much less about the future simply reflects an epistemological difference between the future and the past: the future is no less real than the past; we just know less about it (Mellor 1998). A view was held, for example by Quine
and Putnam
that physical theories such as special relativity, and latterly Quantum mechanics
provide the B-theory with compelling support. http://www.springerlink.com/content/g03038642176k856/ http://docs.google.com/viewer?a=v&q=cache:js7G9mLTnVkJ:host.uniroma3.it/dipartimenti/filosofia/personale/eujap.pdf+Time+slice+ontology,+relativity&hl=en&gl=uk&pid=bl&srcid=ADGEESgn0-XafheZQBvO5dr8P3jwTMYHMU6xRTTIgCykwUdZur_AdZDA81tSWqrNwlyLOcYEFYL8YphYlEHR-naFdN0ihBL7t1j-Qlz-83PTmCzIqcawehiThCeyuDQn5scud9XfCYPU&sig=AHIEtbSz75YBld3pGmA84c0hoq-BMEP-bA
A-theorists on the other hand believe that a satisfactory account of time must acknowledge a fundamental metaphysical difference between past, present and future (Prior 2003). The difference between A-theorists and B-theorists is often described as a dispute about temporal passage or 'becoming'. B-theorists argue that this notion embodies serious confusion about time, while many A-theorists argue that in rejecting temporal 'becoming', B-theorists reject time's most vital and distinctive characteristic. It is common (though not universal) to identify A-theorists' views with belief in temporal passage.
It is also common (though not universal) for B-theorists to be four-dimensionalists
, that is, to believe that objects are extended in time as well as in space and therefore have temporal as well as spatial parts. This is sometimes called a time-slice ontology
(Clark, 1978).
The debate between A-theorists and B-theorists is a continuation of a metaphysical dispute reaching back to the ancient Greek philosophers Heraclitus
and Parmenides
. Parmenides thought that reality is timeless and unchanging. Heraclitus, in contrast, believed that the world is a process of ceaseless change, flux and decay. Reality for Heraclitus is dynamic and ephemeral. Indeed the world is so fleeting, according to Heraclitus, that it is impossible to step twice into the same river. The metaphysical issues that continue to divide A-theorists and B-theorists concern the reality of the past, the reality of the future, and the ontological status of the present.
Philosophy of space and time
Philosophy of space and time is the branch of philosophy concerned with the issues surrounding the ontology, epistemology, and character of space and time. While such ideas have been central to philosophy from its inception, the philosophy of space and time was both an inspiration for and a...
. The labels, A-theory and B-theory
A-series and B-series
A-series and B-series are two different descriptions of the temporal ordering relation among events. The two series differ principally in their use of tense to describe the temporal relation between events...
, are derived from the analysis of time and change developed by Cambridge philosopher J. M. E. McTaggart
J. M. E. McTaggart
John McTaggart was an idealist metaphysician. For most of his life McTaggart was a fellow and lecturer in philosophy at Trinity College, Cambridge. He was an exponent of the philosophy of Hegel and among the most notable of the British idealists.-Personal life:J. M. E. McTaggart was born in 1866...
in The Unreality of Time
The Unreality of Time
The Unreality of Time is the best-known philosophical work of the Cambridge idealist J. M. E. McTaggart. In the paper, first published in 1908 in Mind 17: 457-73, McTaggart argues that time is unreal because our descriptions of time are either contradictory, circular, or insufficient...
, in which events are ordered via a tensed A-series or a tenseless B-series.
Description
Events (or 'times'), McTaggart observed, may be characterized in two distinct, but related, ways. On the one hand they can be characterized as past, present or future, normally indicated in natural languages such as English by the verbal inflection of tenses or auxiliary adverbial modifiers. Alternatively events may be described as earlier than, simultaneous with, or later than others. Philosophers are divided as to whether the tensed or tenseless mode of expressing temporal fact is fundamental. Those who (like Arthur PriorArthur Prior
Arthur Norman Prior was a noted logician and philosopher. Prior founded tense logic, now also known as temporal logic, and made important contributions to intensional logic, particularly in Prior .-Biography:Prior was entirely educated in New Zealand, where he was fortunate to have come under the...
http://hylo.loria.fr/content/papers/files/tense.pdf) take the tensed notions associated with the past, present and future to be the irreducible foundations of temporality and our conceptions of temporal fact, are called A-theorists (or presentists
Presentism (philosophy of time)
Saint Augustine proposed that the present is a knife edge between the past and the future and could not contain any extended period of time. This seems evident because, if the present is extended, it must have separate parts - but these must be simultaneous if they are truly part of the present...
). A-theorists deny that past, present and future are equally real, and maintain that the future is not fixed and determinate like the past. Those who wish to eliminate all talk of past, present and future in favour of a tenseless ordering of events are called B-theorists. B-theorists (such as D.H. Mellorhttp://people.pwf.cam.ac.uk/dhm11/Tense.html and J.J.C. Smarthttp://docs.google.com/viewer?a=v&q=cache:5sRVGv3QVqEJ:faculty.fullerton.edu/jeelooliu/420_(08)_folder/420_Smart_Tenseless_Theory_of_Time.pdf+jjc+Smart,+time&hl=en&gl=uk&pid=bl&srcid=ADGEESj0Xc_Ysa9-LvI6kx2yVfkGcPkoXK9FEOKyrE4BgwzkDZUX__yFJy2jR-It_lvMGyTka4CsBri4Be0eaCaEtdcpl8zXHBsJ6Kl98DrGrftfuOKqqxJTlXNN7-0ok6WIwbHzSwPj&sig=AHIEtbQQz0Y0XiRU3vXT65BXOgavfEy_Ww) believe that the past the present and the future are equally real.
The past, the present and the future feature vary differently in deliberation and reflection. We remember the past and anticipate the future, for example, but not vice versa. B-theorists maintain that the fact that we know much less about the future simply reflects an epistemological difference between the future and the past: the future is no less real than the past; we just know less about it (Mellor 1998). A view was held, for example by Quine
Willard Van Orman Quine
Willard Van Orman Quine was an American philosopher and logician in the analytic tradition...
and Putnam
Hilary Putnam
Hilary Whitehall Putnam is an American philosopher, mathematician and computer scientist, who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, philosophy of mathematics, and philosophy of science...
that physical theories such as special relativity, and latterly Quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
provide the B-theory with compelling support. http://www.springerlink.com/content/g03038642176k856/ http://docs.google.com/viewer?a=v&q=cache:js7G9mLTnVkJ:host.uniroma3.it/dipartimenti/filosofia/personale/eujap.pdf+Time+slice+ontology,+relativity&hl=en&gl=uk&pid=bl&srcid=ADGEESgn0-XafheZQBvO5dr8P3jwTMYHMU6xRTTIgCykwUdZur_AdZDA81tSWqrNwlyLOcYEFYL8YphYlEHR-naFdN0ihBL7t1j-Qlz-83PTmCzIqcawehiThCeyuDQn5scud9XfCYPU&sig=AHIEtbSz75YBld3pGmA84c0hoq-BMEP-bA
A-theorists on the other hand believe that a satisfactory account of time must acknowledge a fundamental metaphysical difference between past, present and future (Prior 2003). The difference between A-theorists and B-theorists is often described as a dispute about temporal passage or 'becoming'. B-theorists argue that this notion embodies serious confusion about time, while many A-theorists argue that in rejecting temporal 'becoming', B-theorists reject time's most vital and distinctive characteristic. It is common (though not universal) to identify A-theorists' views with belief in temporal passage.
It is also common (though not universal) for B-theorists to be four-dimensionalists
Four dimensionalism
In philosophy, four-dimensionalism is an ontological position that an object's persistence through time is like its extension through space and an object that exists in time has temporal parts in the various subregions of the total region of time it occupies.Eternalism is a...
, that is, to believe that objects are extended in time as well as in space and therefore have temporal as well as spatial parts. This is sometimes called a time-slice ontology
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
(Clark, 1978).
The debate between A-theorists and B-theorists is a continuation of a metaphysical dispute reaching back to the ancient Greek philosophers Heraclitus
Heraclitus
Heraclitus of Ephesus was a pre-Socratic Greek philosopher, a native of the Greek city Ephesus, Ionia, on the coast of Asia Minor. He was of distinguished parentage. Little is known about his early life and education, but he regarded himself as self-taught and a pioneer of wisdom...
and Parmenides
Parmenides
Parmenides of Elea was an ancient Greek philosopher born in Elea, a Greek city on the southern coast of Italy. He was the founder of the Eleatic school of philosophy. The single known work of Parmenides is a poem, On Nature, which has survived only in fragmentary form. In this poem, Parmenides...
. Parmenides thought that reality is timeless and unchanging. Heraclitus, in contrast, believed that the world is a process of ceaseless change, flux and decay. Reality for Heraclitus is dynamic and ephemeral. Indeed the world is so fleeting, according to Heraclitus, that it is impossible to step twice into the same river. The metaphysical issues that continue to divide A-theorists and B-theorists concern the reality of the past, the reality of the future, and the ontological status of the present.
External links
- Markosian, Ned, 2002, "Time", Stanford Encyclopedia of Philosophy
- Arthur Prior, Stanford Encyclopedia of Philosophy