Everytime I try to read an explanation of both I don’t really understand the difference. Saying “this happened in the past” and “this happened before that” is just using different words to describe the exact same thing to me. I guess I’m also not understanding the implications of this distinction.
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This is a bit of a head melt, but they seem to kinda be saying the same thing from different perspectives. In science, everything that happens can be observed 2 ways. From your perspective, you are standing still. From the perspective of someone on a spaceship, you are rotating with the earth, and are definitely not still.
Theory A is from the perspective of someone living in the timeline being described, so things are described as in the distant past, recent past, present, future, and distant future. In this system though, “present” isn’t easily defined. Is “present” now, as you read that word, or is it now as you read it again. Both times you just read “now” are in the past, so it’s kinda murky for describing things. Tomorrow is in the future. Until tomorrow. Then it’s the present. And then it’s the past.
Theory B tries to remove subjective experience from time. It just states thing x happened before thing y. It’s less murky, and there’s no tense included. Theory B also kinda suggests that tenses don’t exist maybe, and that the past and future and present are constructs of our minds to help us understand time
I’m not a specialist, just trying to break down what I just read.
“This happened in the past” implies that there is a special point in time, the present, that we are judging everything else relative to. And, importantly, the truth of the claim “this happened in the past” changes over time. At present, “the 2024 Olympics happened in the past” is false, but presumably at some point it will become true.
The B theory just places events relative to each other and does not privilege any particular time as “the present”.
And this is really just one building block of some philosophical viewpoints about time. The person who came up with the distinction (a guy with the incredible name of John McTaggart Ellis McTaggart) thought that neither of these perspectives makes sense and that time isn’t real. Since then, there have been many developments in physics that are relevant to this discussion, and philosophers’ views have shifted to take them into account.
You can think of time like we classically think of it. Where I experience a past, present, and future. These may be convenient assumptions our mind makes to help understand reality.
Alternatively, the speed of causality in the universe is exactly the speed that light moves. Consequently, light does not experience time. Its’ entire existence happens all at the same time. So with that thinking, the external relative ‘time’ we experience may in fact be a derivative of our speed.
Firstly, “A Theory” and “B Theory” (or A Series and B Series) are not physics. They are metaphysics; a type of philosophy.
They build a bit on real physics, but it is worth noting that the early work on A Series and B Series ordering of events was done in 1908, in the earliest days of our modern understanding of time from a scientific point of view. They are not science.
Roughly speaking, A Series describes events in relation to a particular present. It uses tenses, and tells you when things happened in relation to a “now.”
B series describes events in relation to each other, with no specified present.
The example Wikipedia gives are the statements “it is raining today” and “it rained on 3 October 2023.” The first statement is A Series – it is based on a particular present (it changes meaning depending on when we say it), whereas the second is B series (the statement works whenever we are).
That then gets us into B Theory. B Theory is an idea that time is tenseless; that the flow of time is a subjective illusion created by our own consciousness, and that past, present a future are all equally real.
From a physics perspective, this is kind of interesting, but not really; we know that the flow of time is relative, but it is not subjective, and there are absolutes.
Years ago I had a talk with a physicist who worked on time research, and he described attending a conference on time with a bunch of physicists and philosophers. He was somewhat dismissive of the philosophers; they were struggling with basic concepts that have been understood by physics for over a century.
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