If you want to conclude that a given variable has a causal relation with a second variable, you have to rule out other possible causal variables. The principle of causation involved here is the -

Ruling out other possible causal variables to claim a genuine cause reflects the internal validity rule.

Internal validity is the degree to which an effect can be attributed to the studied variable and not to rivals.

The covariance rule only requires that the two variables change together, which alone cannot prove cause.

The temporal precedence rule requires the cause to occur before the effect in time.

There is no recognised principle called the causal ambiguity rule in the logic of causation.

The three joint conditions of causation are covariation, time order and the elimination of alternative causes.