# Does retrocausality follow from logic?

• B
Gold Member

## Main Question or Discussion Point

I can't remember where this subject came forward in my topics, so I created a new topic.

Suppose that:
1. If X happens, we observe A, and:
2. If Y happens, we observe B.
Could we then say:
1. If we observe A, Y did not happen, and:
2. If we observe B, X did not happen,
if we apply this to quantummechanical events {X,Y} and observations {A,B} thereof?

{X,Y} are exclusive, {A,B} are exclusive.
In case of binary events: X=¬Y and A=¬B.

And if we could manipulate the observation, would it then (logically) be possible to manipulate which event happened by doing so?

A way to manipulate the observation could perhaps be choice of measurement basis.

This is mainly logic applied to quantum mechanics.

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fresh_42
Mentor
I can't remember where this subject came forward in my topics, so I created a new topic.

Suppose that:
1. If X happens, we observe A, and:
2. If Y happens, we observe B.
Could we then say:
1. If we observe A, Y did not happen, and:
2. If we observe B, X did not happen,
No, we can not. O.k. we can, but it is wrong. You imply a dependence and continue to argue based on this false assumption, hence everything below is wrong.
... if we apply this to quantummechanical events {X,Y} and observations {A,B} thereof?

{X,Y} are exclusive, {A,B} are exclusive.
In case of binary events: X=¬Y and A=¬B.

And if we could manipulate the observation, would it then (logically) be possible to manipulate which event happened by doing so?

A way to manipulate the observation could perhaps be choice of measurement basis.

This is mainly logic applied to quantum mechanics.

• entropy1
Gold Member
In my view, there is an issue with retrocausality:

Suppose A excerts a retrocausal influence on history H. Then, if this influence is excerted by free will in the present, then H will change, and history is subjective (because it adapts to the free will of A).

If H is objective it is as it is, and if A has excerted influence on it, A would have no free will, for H is objective and will not change.

If H is objective and A has free will, then there cannot be retrocausal influence.

So we have three properties that cannot hold all three: objectivity, free will and retrocausality.

Last edited:
DrChinese