Tensions in Practice: A fixed past in tension with a cause-preserving alternative history¶
A declared toy garden rule yesterday
Yesterday there was no rain, so the automatic sprinkler ran and the path became wet. The toy rules are: the sprinkler runs exactly when it does not rain; either rain or spray wets the path. To imagine the sprinkler off, we can force it off while holding yesterday’s lack of rain fixed, producing a dry path. Or we can alter the prior weather to rain, so the ordinary rule switches it off and the path stays wet. These are different counterfactual questions.
Isolate an action change
Hold the prior weather fixed while changing the sprinkler action.
Preserve the ordinary control rule
Find an altered history in which the sprinkler would naturally be off.
Why these aims pull against each other
The same changed antecedent can be reached by overriding a downstream action or changing its upstream cause; the consequences need not match.
Choose an arrangement to see what changes and what remains difficult.
Arrows express the stated dependencies or transformations, not measured effects. All example quantities are invented.
What this choice protects
What it costs
When it fits
Compare the arrangements
Hold weather fixed
Keep yesterday’s no-rain condition and intervene to turn the sprinkler off.
- What it protects
- The alternative isolates the consequence of the changed action under that fixed past.
- What it costs
- The sprinkler no longer follows its ordinary automatic rule in this imagined intervention.
- When it fits
- Fits an explicitly intervention-like question about overriding the sprinkler.
Illustration note: The incoming weather-to-sprinkler rule is suspended; it cannot also be enforced unchanged.
Change the upstream history
Imagine rain yesterday; the ordinary automatic rule then keeps the sprinkler off.
- What it protects
- The counterfactual keeps the control mechanism intact.
- What it costs
- It changes an earlier fact and no longer isolates the sprinkler action.
- When it fits
- Fits a backtracking question explicitly allowing prior causes to differ.
Illustration note: This is not an estimate of the effect of manually switching off the sprinkler.
What this illustration does—and does not—establish
The source supplies the tension. The invented setting, alternatives and any numbers illustrate a limited comparison; each arrangement retains its stated costs and conditions.
- All garden rules are stipulated and omit drainage, timing and other sources of water.
- The counterfactual concerns known-false alternatives to yesterday, not a forecast of tomorrow.
- Neither selection of alternative history is universally correct; it must match the question.
Source entries
Counterfactuals
This source passage supplies the contextual tension. The concrete arrangements and schematic examples are editorial illustrations, not measured findings.
Backtracking vs Forward-Tracking — Past-Fixed vs Past-Altered Counterfactuals
Given an antecedent, do we hold the actual past fixed and forward-track to the consequent (causal-relevant, standard analysis), or do we allow past changes to accommodate the antecedent (backtracking, often rejected)?
The source operation
Counterfactual reasoning is the construction and evaluation of claims of the form "if A had been the case, then B would have been (or would likely have been) the case," where A is contrary to actual fact and the reasoning asks what would have followed under that altered condition, often for the sake of identifying causal relationships, evaluating decisions, assigning moral or legal responsibility, or exploring alternative possibilities.