When scientists announced the detection of gravitational waves in 2016, headlines declared it a triumph of human knowledge. Einstein's prediction, made a century earlier, had finally been confirmed. But what exactly had progressed? Did we get closer to the truth about the universe? Did we simply solve a long-standing puzzle? Or did we just add another chapter to an ever-changing story?

These questions might seem pedantic, but they cut to the heart of what science actually accomplishes. If we don't understand what scientific progress means, we can't properly evaluate scientific claims or appreciate why science deserves its cultural authority.

The most intuitive view of scientific progress holds that science gradually approaches the truth. Newton's physics was good, but Einstein's was better—more accurate, more comprehensive. On this view, scientific theories are like maps that become increasingly detailed and reliable over time.

This perspective, called scientific realism, suggests that mature scientific theories genuinely describe unobservable entities like electrons, genes, and gravitational waves. When our best theories consistently predict novel phenomena and survive rigorous testing, that's evidence they're tracking something real. The success of science would be a miracle otherwise.

But critics point to a troubling pattern: past theories we once considered successful have been abandoned as false. Nineteenth-century physicists believed in luminiferous ether—a substance supposedly filling all space—and their theories made accurate predictions. Yet ether doesn't exist. If previous "successful" theories were wrong about fundamental entities, why trust current ones?

Takeaway

Scientific success suggests our theories capture something real, but the history of discarded concepts reminds us that empirical success alone doesn't guarantee truth.

Philosopher Larry Laudan proposed a different measure: scientific progress means enhanced problem-solving effectiveness. Science advances when it resolves more empirical problems (explaining observations) and conceptual problems (internal inconsistencies or conflicts with other knowledge).

This view sidesteps thorny questions about truth entirely. We don't need to know whether electrons "really" exist to recognize that atomic theory solves countless problems—explaining chemical reactions, predicting spectral lines, enabling technological applications. Progress is measured by what science can do, not what it claims to describe.

The problem-solving view also explains why scientists sometimes prefer theories with less empirical support. A theory might solve fewer immediate problems but resolve deep conceptual tensions, making it more progressive overall. Einstein's general relativity initially had less empirical support than Newton's mechanics but eliminated troubling inconsistencies about gravity's instantaneous action at a distance.

Takeaway

Measuring progress by problems solved rather than truth approached shifts focus from what science describes to what science achieves—a more modest but perhaps more defensible standard.

Thomas Kuhn challenged both previous views with a radical claim: science doesn't accumulate knowledge progressively at all. Instead, it alternates between "normal science" (puzzle-solving within accepted frameworks) and "revolutionary science" (paradigm shifts that replace entire worldviews).

When paradigms shift—from Newtonian to Einsteinian physics, from Ptolemaic to Copernican astronomy—the change isn't simply additive. Scientists adopt new concepts, new methods, even new standards for what counts as a good explanation. The old and new frameworks can be so different that they're incommensurable—not directly comparable by shared criteria.

If Kuhn is right, calling later science "better" becomes problematic. Better by whose standards? Each paradigm sets its own criteria for success. This doesn't mean scientific change is irrational, but it suggests progress might be more like biological evolution—adaptation to changing conditions—than like approaching a fixed destination called "truth."

Takeaway

Scientific change might resemble evolution more than a journey toward a destination—adaptive responses to intellectual environments rather than steps toward a predetermined truth.

These three accounts aren't entirely incompatible. Perhaps science progresses in problem-solving capacity because it approximates truth, with occasional revolutionary disruptions reshaping what problems matter most. The debate remains unresolved.

What's clear is that "progress" in science isn't straightforward accumulation of facts. Understanding this complexity doesn't diminish science's achievements—it deepens our appreciation for what scientific inquiry actually involves and what we can reasonably claim to know.