Current intelligence definitions are either partial or do not provide an actionable evaluation of intelligence, something tangible which can be used to quantify the potential of a given AGI. In absence of this definition we commonly define intelligence as the result accuracy of an intelligence test, for instance an IQ test, but this is prone to evaluation overfitting. We review existing definitions and then we consider a new heuristic definition, which we call PGI index or Pragmatic General Intelligence index, which relates intelligence to the ability to perform arbitrary tasks, but in which task accuracy is just one of the factors contributing to intelligence. In a toy model, we compute the PGI Index of an average human and of the Gato AI.