Judea Pearl’s causal calculus provides a formal framework for reasoning about causality.The key operator is do(⋅), representing external intervention.Structural equation modeling (SEM) is a cornerstone of counterfactual reasoning.Counterfactuals are hypothetical scenarios: “What would Y have been if X were different?”Causal inference underpins critical applications in AI.Counterfactual reasoning provides a principled approach to ensuring fairness, enhancing explainability, and optimizing decisions in dynamic systems.Causal inference in AI faces several theoretical and computational challenges.One exciting frontier is counterfactual generative adversarial networks (CGANs).Causality also has profound implications for scientific discovery.There are several Python libraries designed for basic causal inference tasks.