Acceleration:

A cat will accelerate at a constant rate, until the cat gets good and ready to stop.

Aerodynamics:

If it flies, a cat will chase it.

Bag/Box Occupancy:

All bags and boxes in a given room must contain a cat within the earliest possible nanosecond.

Dinner Table Attendance:

A cat will attend all meals when anything good is served.

Disinterest:

A cat's interest level will vary in inverse proportion to the amount of effort a human expends in trying to interest the cat.

Electric Blanket Attraction:

Turn on an electric blanket and a cat will jump into bed at the speed of light.

Elongation:

A cat can make its body long enough to reach just about any counter top that has anything remotely interesting on it.

Embarrassment:

A cat's irritation rises in direct proportion to the cat's embarrassment times the amount of human laughter.

Energy Conservation--First Law:

A cat knows that energy can neither be created nor destroyed and will therefore use as little energy as possible.

Energy Conservation--Second Law:

A cat knows that energy can only be stored by a lot of napping.

Fluid Displacement:

A cat immersed in milk will displace its own volume, minus the amount of milk consumed.

Furniture Replacement:

A cat's desire to scratch furniture is directly proportional to the cost of the furniture.

Gravity:

The cat knows that gravity works, even when sound asleep.

Inertia:

A cat at rest will tend to remain at rest, unless acted upon by some outside force, such as the opening of cat food or a nearby scurrying mouse.

Landing:

A cat will always land in the softest place possible.

Magnetism:

All blue blazers and black sweaters attract cat hair in direct proportion to the darkness of the fabric.

Milk Consumption:

A cat will drink its weight in milk, squared, just to show you that the cat can do it.

Motion:

A cat will move in a straight line, unless there is a really good reason to change direction.

Obedience Resistance:

A cat's resistance varies in direct proportion to a human's desire for the cat to do something.

Obstruction:

A cat will lay on the floor in such a position as to obstruct the maximum amount of human foot traffic.

Pill Rejection:

Any pill given to a cat has the potential energy to reach escape velocity.

Random Comfort Seeking:

A cat will always seek (and usually take over) the most comfortable spot in any given room.

Refrigerator Observation:

If a cat watches a refrigerator long enough, someone will come along and take out something good to eat.

Rug Configuration:

No rug may remain in its naturally flat state for very long.

Sleeping:

A cat will sleep with people whenever possible, in a position as uncomfortable for the people involved as possible, while maintaining the cat's own comfort.

Stretching:

A cat will stretch to a distance proportional to the length of the nap just taken.

Thermodynamics:

Heat flows from a warmer to a cooler body, except in the case of a cat, in which case all heat flows to the cat.