Newtonian Physics. For every action there is an opposite and equal reaction.

By now I think we take Newtons laws of physics to be true. No fancy quantum stuff here dealing with the movement of atoms.

So if I have an action resulting in this awesome lunch of corn tortillas, carne asada I bbq-ed, salsa, cheese, lettuce and carrots

Then its equal reaction must be parking my truck on top of my favorite pair of running shoes

Or paying Porsche $300 for a new car battery. Either way, what goes up must come down. Especially if we're talking about me on a mountain bike. Which we're not.