A-series and B-series
Encyclopedia
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. The terms were introduced by the Scottish idealist
philosopher John McTaggart
in 1908 as part of his argument for the unreality of time, but since then they have become widely used terms of reference in modern discussions of the philosophy of time.
From a second point of view, one can order events according to a different series of temporal positions by way of two-term relations which are asymmetric, irreflexive and transitive: "comes before" (or precedes) and "comes after" (or follows). This is the B-series, and the philosophy which says all truths about time can be reduced to B-series statements is the B-theory of time
.
The logic and the linguistic expression of the two series are radically different. The first is tensed and the second is tenseless.
For example, the assertion "today it is raining" is a tensional assertion because it depends on the temporal perspective—the present—of the person who utters it, while the assertion "It rains on the 15th of June, 1996" is non-tensional because it does not so depend. From the point of view of their truth-values, the two propositions are identical (both true or both false) if the first assertion is made on June 15, 1996. The non-temporal relation of precedence between two events, say "E precedes F", does not change over time
(excluding from this discussion the issue of the relativity of temporal order of causally disconnected events in the theory of relativity). On the other hand, the character of being "past, present or future" of the events "E" or "F" does change with time. In the image of McTaggart the passage of time consists in the fact that terms ever further in the future pass into the present...or that the present advances toward terms ever farther in the future. If we assume the first point of view, we speak as if the B-series slides along a fixed A-series. If we assume the second point of view, we speak as if the A-series slides along a fixed B-series.
Idealism
In philosophy, idealism is the family of views which assert that reality, or reality as we can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. Epistemologically, idealism manifests as a skepticism about the possibility of knowing any mind-independent thing...
philosopher John 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 1908 as part of his argument for the unreality of time, but since then they have become widely used terms of reference in modern discussions of the philosophy of time.
McTaggart's use of the A-series and B-series
According to McTaggart, there are two distinct modes in which all events can be ordered in time. In the first mode, events are ordered by way of the non-relational singular predicates "is past", "is present" and "is future." When we speak of time in this way, we are speaking in terms of a series of positions which run from the remote past through the recent past to the present, and from the present through the near future all the way to the remote future. The essential characteristic of this descriptive modality is that one must think of the series of temporal positions as being in continual transformation, in the sense that an event is first part of the future, then part of the present, and then past. Moreover, the assertions made according to this modality imply the temporal perspective of the person who utters them. This is the A-series of temporal events.From a second point of view, one can order events according to a different series of temporal positions by way of two-term relations which are asymmetric, irreflexive and transitive: "comes before" (or precedes) and "comes after" (or follows). This is the B-series, and the philosophy which says all truths about time can be reduced to B-series statements is the B-theory of time
B-Theory of time
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...
.
The logic and the linguistic expression of the two series are radically different. The first is tensed and the second is tenseless.
For example, the assertion "today it is raining" is a tensional assertion because it depends on the temporal perspective—the present—of the person who utters it, while the assertion "It rains on the 15th of June, 1996" is non-tensional because it does not so depend. From the point of view of their truth-values, the two propositions are identical (both true or both false) if the first assertion is made on June 15, 1996. The non-temporal relation of precedence between two events, say "E precedes F", does not change over time
(excluding from this discussion the issue of the relativity of temporal order of causally disconnected events in the theory of relativity). On the other hand, the character of being "past, present or future" of the events "E" or "F" does change with time. In the image of McTaggart the passage of time consists in the fact that terms ever further in the future pass into the present...or that the present advances toward terms ever farther in the future. If we assume the first point of view, we speak as if the B-series slides along a fixed A-series. If we assume the second point of view, we speak as if the A-series slides along a fixed B-series.
External links
- Time---Notes on McTaggart and the Unreality of Time- Trinity College Seminar on Time.