Laws of Nature The Regularity Theory

Laws Contingent vs. Necessary Laws Deterministic vs. Probabilistic Law Leibniz’s Law: For all x and y, if x=y then x and y share all the same properties. Newton’s Law: For all x and y, if xy, then x and y exert a force on each other inversely proportional to the square of the distance between them. Deterministic vs. Probabilistic Law Strict vs. Ceteris Paribus Laws

The Regularity Theory The Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization. Leibniz’s Law The Chuck Norris Law The Titius Principle Newton’s Law

The Regularity Theory The Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization. Objection #1: Restricted Generalizations All the objects in my pocket are copper.

The Regularity Theory The Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization. Objection #2: Vacuous Generalizations All plaid panda weigh exactly five kilograms.

The Regularity Theory The Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization. Objection #3: Accidental Generalizations All gold spheres are less than a mile in diameter.

The Regularity Theory The Revised Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization that . The Revised Regularity Theory: For all P, P is a law of nature iff P is a contingently true generalization that would remain true under a range of counterfactual alternatives. Objection: Circularity

Counterfactuals It is of the first importance to avoid big, widespread, diverse violations of law. It is of the second importance to maximize the spatio-temporal region throughout which perfect match of particular fact prevails. It is of third importance to avoid even small, localized, simple violations of law. It is of little or no importance to secure approximate similarity of particular fact, even in matters that concern us greatly.