This book investigates the ontological status of powers and capacities in nature, arguing that they are essential components of scientific inquiry that can be empirically tested. Nancy Cartwright, a philosopher of science, challenges the long-standing empiricist tradition that has historically excluded capacities from scientific discourse. By examining the intersection of econometrics and modern physics, she demonstrates that causal capacities are not merely theoretical abstractions but are measurable entities within scientific practice. The work provides a robust framework for understanding how probabilities function as indicators of these underlying causal powers.

Experts in the philosophy of science recognize this work as a foundational text for challenging traditional empiricist views on causality. Readers frequently note the technical density of the prose, which requires a strong background in both philosophy and scientific methodology to fully grasp the arguments presented.