§1 Judging Scientific Theories

In the common imagination, science is often misunderstood as a simple collection of “proven facts.” In reality, science is a dynamic process of inference and revision. To be a Reasonable Person, you must understand that scientific “truth” is not found in a textbook but in the rigor of the methods used to judge one theory against another.

1.1 The Hypothetical-Deductive Method

Most modern science doesn’t just collect data blindly; it follows a specific logical loop known as the Hypothetical-Deductive Method. This is the formal “engine” of scientific discovery.

1. Observation: You notice something that needs an explanation (e.g., “The plants near the window are taller than the ones in the corner”).

2. Hypothesis Formulation: You propose a tentative explanation (e.g., “Plants grow taller when they receive more sunlight”). This is essentially an Inference to the Best Explanation (IBE).

3. Deduction (Prediction): You ask: “If my hypothesis is true, what else must be true?” You deduce a specific, measurable prediction (e.g., “If I move the corner plants to the window, they will grow 2 inches in a week”).

4. Testing: You perform the experiment. If the prediction fails, the hypothesis is rejected or modified. If it succeeds, the hypothesis is corroborated (strengthened), though never “proven” with absolute 100% certainty.

1.2 The Criteria of Adequacy in Science

As we discussed in Chapter 9, not all explanations are equal. Scientists use specific logical benchmarks to decide which theory “wins.” While all five criteria are important, science places a heavy premium on two in particular:

• Testability (Falsifiability): If there is no possible observation that could prove a theory wrong, it isn’t science—it’s dogma. A scientific theory must “put its neck on the line.”

• Fruitfulness: A “fruitful” theory doesn’t just explain what we already know; it predicts things we haven’t even discovered yet.

  • Example: Einstein’s Theory of General Relativity wasn’t just accepted because it was “pretty.” It was accepted because it predicted that light would bend around stars—a “fruitful” prediction that was later confirmed during a solar eclipse.

1.3 The “Tentative” Nature of Science

One of the most difficult concepts for non-scientists to grasp is that science is provisional. Because science relies on Induction (Chapter 7), it can never reach the absolute certainty of a mathematical proof ($2+2=4$).

• Evidence vs. Proof: Scientists rarely use the word “proof.” Instead, they talk about the Weight of Evidence.

• The Self-Correcting Mechanism: The strength of science isn’t that it is always right, but that it has a built-in mechanism for admitting it was wrong when a better, more “adequate” theory comes along.

§1 Summary Table: Judging a Scientific Claim