What is Science?

Science is often misunderstood as a static collection of facts or a quest for absolute, irrefutable truth. In this chapter, the authors argue that science is better understood as a rigorous, critical method. At its core, science is a strategy for explaining the world by generating statements that are falsifiable—meaning there must be some imaginable observation that could prove the statement wrong. If a claim cannot be tested or is true by definition (a tautology), it falls outside the realm of science.

The authors outline a systematic process for scientific inquiry. It begins with a puzzle or an observation that contradicts existing expectations. Researchers then construct a theory or model—a set of logically consistent statements—to explain why the observed phenomenon occurred. A good model is a simplified picture of reality, designed not for descriptive accuracy, but for utility in explaining a specific phenomenon. From these models, researchers derive testable implications (hypotheses). The final steps involve testing these implications against empirical evidence and evaluating the results. Crucially, this process is deductive: we start with a theory and test it, rather than starting with observations and attempting to induce a theory, which the authors argue is logically problematic.

The authors emphasize that scientific knowledge is inherently tentative. Because we can never prove a theory is true, we instead focus on falsificationism. This approach holds that we gain confidence in a theory only when it survives rigorous attempts to prove it wrong. Logic plays a central role here: while confirming observations do not prove a theory, a single well-designed test that contradicts a theory can logically compel us to reject it. This asymmetry is why scientists should prioritize "critical tests"—attempts to distinguish between competing models by identifying where their predictions conflict.

The chapter concludes by dispelling common myths about science. Science does not provide absolute certainty, nor does it require experimental manipulation or laboratory settings. Furthermore, while the scientific method is value-neutral, the scientific community is not. Because individual scientists carry biases, the authors argue that diversity within the scientific community is essential. By subjecting claims to criticism from diverse perspectives, the community can reach a consensus that is more robust than any individual's work.