Dilemma
Could causation work backwards?
If the laws of physics are time-symmetric, what makes causes precede their effects? And if the asymmetry isn't metaphysical, could retroactive causation be coherent?
Context
Quantum delayed-choice experiments, the apparent time-symmetry of fundamental physical laws, the occasional reading of certain religious doctrines as involving retroactive divine action — the question of whether causation runs strictly forward or can in principle run backward has been alive for centuries and is unsettled. The question matters for interpretations of quantum mechanics, for the metaphysics of memory and anticipation, and for some philosophical theologies (does prayer-now affect past-then?). The disagreement rests on whether time has a real directionality or only a conventional one.
Why it matters
How a tradition reads time direction determines whether retrocausation is structurally impossible, metaphysically open, or already implicit in the framework. The answer shapes interpretations of quantum mechanics, the philosophical status of certain religious practices, and the deeper question of whether the past is genuinely settled or only ordinarily presented as settled.
The coordinates that split the schools
The stances
Causation runs one way — the arrow of time is real and structural.
85 schoolsOn this view, time has a real direction, and causation follows it. Retrocausation isn't merely rare or hard to achieve; it is structurally ruled out by what time is. The thermodynamic arrow, the apparent direction of mental experience, the impossibility of changing the past — these aren't conventions; they are what time is.
Where this stance leads ⓘ
- 1% The asymmetry is real because time itself has a real direction. on Is the asymmetry between memory and anticipation a real feature of time, or just of us?
- 1% The arrow is real and structural; the asymmetry isn't an artifact of description. on Is the arrow of time a real feature of the cosmos, or only of how we describe it?
- 1% Damage is real and permanent on the relevant timescales. There is no recovery; there is only limitation. on Is environmental damage ever truly permanent?
- 1% Civilizational complexity is hard to build and easy to lose; recovery is at best partial. on Can a civilization recover from collapse?
- 1% Entropy is what time is. The moral weight, if any, is the weight of working against the current. on Does the second law of thermodynamics mean something morally?
Time has no privileged direction; retrocausation is coherent in principle.
1 schoolOn this view, the apparent asymmetry of past and future is a feature of perspective, not of the underlying reality. Causation could in principle run backward; what we describe as the present causing the future could be redescribed without loss as the future co-determining the present.
Past, present, and future are conventional designations; the question doesn't quite arise.
3 schoolsOn this view, the categories of past, present, and future are useful designations rather than real directions of an underlying time. The question of whether causation could run backward presupposes the directionality the view denies. Causation just is the pattern of correlation we find; calling it forward or backward is a matter of which end you're looking from.
Time is structured as return; 'forward' and 'backward' are local features of the cycle.
26 schoolsOn cyclical views, time is not a straight arrow but a structure of return. What appears as forward causation in one phase is part of the larger cycle in which past and future continuously give onto each other. Retrocausation as ordinarily conceived doesn't arise; the categories that support the framing don't quite apply.
Where this stance leads ⓘ
- 1% Past, present, and future are bound in cycles — duties span generations as a matter of course. on How much weight do future people deserve?
- 1% The past is part of a cycle one keeps returning to; regret is one of the gates of the cycle. on Is regret rational?
- 1% Past beings are part of the cycle; we owe them what we owe ancestors. on Do we owe extinct species something we cannot give them?
- 1% Loss is part of cycles; what disappears returns in another form. on Is environmental damage ever truly permanent?
- 1% Civilization rises and falls in cycles; recovery is structural to history. on Can a civilization recover from collapse?
Time branches; 'forward' picks out the branch you're in, not the only available direction.
5 schoolsOn branching views, time is a tree of possibilities. Causation within a branch runs in the ordinary way, but the larger structure of branches embraces possibilities that this branch's forward arrow doesn't capture. Quantum-mechanical retrocausation, in the delayed-choice sense, finds natural framing here.
Where this stance leads ⓘ
- 1% The future branches — what we owe depends on which branch we create. on How much weight do future people deserve?
- 1% Other branches exist; regret tracks roads not taken that are nonetheless real. on Is regret rational?
- 1% Extinction is path-dependent; the species exists in branches we didn't take. on Do we owe extinct species something we cannot give them?
- 1% Prayer changes the pray-er, not the prayed-for. on Can prayer for someone far away affect them?
- 1% Coincidence is exactly what the math says it is. The pattern is in the noticer. on Are coincidences ever more than coincidence?
From the One's vantage, causation itself is a conventional category.
13 schoolsOn non-dual views, 'causes' and 'effects' name the way the apparent plurality of events relates to itself; at the level of the underlying reality there is nothing distinct enough to be in causal relation. Retrocausation as a metaphysical question presupposes the dualistic framing the view denies. The question doesn't quite arise; the conventional practice of attributing causes remains useful at the conventional level.
Where this stance leads ⓘ
- 1% Individuality dissolves into the One. on What happens to "you" when you die?
- 1% From the standpoint of the One, the question doesn’t apply in the form it is asked. on When does a person begin?
- 1% All union is participation in the One — particular forms are conventional. on What is marriage?
- 1% Money's apparent diversity is convention over a single underlying value. on What is money?
- 1% Nations are conventional partitions of a single humanity. on What is a nation?
Schools the coordinates don't place
These schools don't satisfy any stance's coordinate pattern strongly enough to be assigned — either because they decline to commit on the question (Confucianism is famously silent on what comes after; Pyrrhonian and pragmatist traditions suspend judgment), or because their attribute signature crosses categories in a way the five buckets don't capture.