For more than half a century, philosopher Nancy Cartwright has examined one of the most fundamental questions in modern knowledge: how far can science truly explain the world around us?
The American philosopher, recognised as one of the leading figures in contemporary philosophy of science, has spent her career questioning whether scientific laws alone are enough to understand complex realities. From hospitals and public health systems to economic policies and government decisions, Cartwright has explored what happens when scientific theories move beyond controlled environments and encounter the unpredictability of real life.
In an interview with Spanish newspaper El País following her recognition with the Fundación BBVA Frontiers of Knowledge Award in Humanities, Cartwright reflected on the limits of scientific certainty, the importance of combining different research methods, and the growing public distrust toward scientific institutions.
Cartwright’s intellectual journey began at an early age. Growing up in New Castle, Pennsylvania, she was raised in a Calvinist educational environment that encouraged her to think about questions of existence, morality, and the meaning of good and evil. Those early reflections eventually shaped a career focused on understanding how humans build knowledge and how societies use it.
Her work has challenged the belief that one discipline or one method can provide complete answers to the world’s problems. According to Cartwright, scientific progress often depends on collaboration between different fields rather than isolation within specialised areas.
“When a discipline works alone, it can advance greatly in refining its tools,” she explained. A biologist, for example, can use controlled experiments to isolate variables and understand how a system operates. A physicist can study precise conditions to describe specific processes. But when scientific knowledge is applied to real-world challenges, she argued, additional expertise becomes necessary.
She pointed to advanced physics experiments as an example. Building instruments capable of testing theories such as relativity requires more than mathematical formulas. It depends on specialists in engineering, materials science, optics, and other technical fields. For Cartwright, the idea that equations alone can explain reality ignores the complexity involved in applying scientific knowledge.
Her philosophical approach also challenges traditional assumptions about determinism — the idea that events follow predictable patterns in all circumstances.
Cartwright argues that scientific predictions often work only under specific conditions. If a ball is dropped in a controlled environment, its movement can be calculated with great accuracy. But when external factors such as wind or magnetic forces are introduced, predicting the outcome becomes far more complicated.
The lesson, she argues, is not that science is weak, but that scientific explanations have limits and must be understood within the circumstances where they are developed.
A central part of Cartwright’s career has focused on causality — understanding how one event produces another. She said her work emerged alongside a broader movement among philosophers and social scientists who sought to restore the importance of cause-and-effect analysis after it had been reduced in some areas of philosophy.
She highlighted randomised clinical trials as one example of a method that can demonstrate the effects of medical treatments when carefully designed. However, she warned against treating any single approach as a universal solution.
In fields such as development economics and public health, Cartwright said evidence-based methods have transformed decision-making. She pointed to the growing use of randomised controlled trials, including research promoted by institutions such as the Massachusetts Institute of Technology (MIT), as an important development in measuring the impact of policies and interventions.
At the same time, she cautioned that relying only on one form of evidence risks overlooking important factors that cannot always be measured through a single methodology.
Cartwright’s reflections come at a time when trust in science and experts has declined in many societies. Asked by El País about growing scepticism toward scientific authority, she said the issue was complicated and required perspectives beyond philosophy, including sociology and anthropology.
Drawing from her own experience growing up in Pennsylvania, she described communities where generations of unemployment have contributed to frustration and a sense of abandonment by institutions.
She said some people’s distrust of science may be connected to a broader feeling that the systems around them have failed to provide security or opportunity.
“I think people have become tired and feel that the system has abandoned them,” she said, while acknowledging that fully understanding the phenomenon requires wider social analysis.
Beyond public trust, Cartwright also discussed the relationship between philosophy and natural sciences. Although she initially studied mathematics, she argued that science and philosophy continue to depend on each other because many scientific questions involve deeper conceptual issues.
She recalled her work on quantum mechanics, where questions about the meaning of equations, scientific models, and concepts such as different quantum states require philosophical reflection alongside mathematical analysis.
During her time at Stanford, she said many physics students became interested in philosophy because their scientific training had focused heavily on equations but offered fewer opportunities to examine what those equations actually meant.
For Cartwright, philosophy provides a space where scientists can step back and question the assumptions behind their work.
As societies confront challenges ranging from healthcare crises to economic inequality and declining institutional trust, Cartwright argues that science must remain connected to broader forms of understanding. Evidence remains essential, she says, but applying knowledge effectively requires cooperation across disciplines and a willingness to recognise the complexity of the world science seeks to explain.
