1. Laws of Nature
The Regularity Theory

2. 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

3. 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

4. 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.

5. 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.

6. 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.

7. 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

8. 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.