### Appendix 8

## Why Quantize?

In the absence of gravity, the spacetime quanta are rigid to the standard forces. This provides the basis special relativity, which tells us that speed slows aging, making it possible to think about visiting the stars. A gravitational field compresses the quantum length and time interval, while keeping the velocity of light constant. This gives us acceleration, shrinking of time and length, and black holes.

Which brings up an important question. Why turn to quantized spacetime when we have advanced our knowledge in continuous spacetime to encompass possible trips to the stars and weird objects like black holes? Well, as its name suggests, continuous spacetime is not split up into little pieces: it is continuous and infinitely divisible. That can leave you with a piece of spacetime that has no size at all. Which, in turn, makes strings of infinities appear in your theory. So, you conjure up opposite infinites to balance them out to find out what’s behind them. It is what one of the inventors of this clever wheeze, Richard Feynman, called a “dippy approach . . . Hocus pocus.” And there are other problems, like the logical contradiction of assuming an entity can have two totally contradictory properties, being both a particle and a wave. Or a black hole whose stability depends on an object that does not obey the laws of physics. Would you board an aircraft stabilized that way?

There is no reason to think that nature acts in these peculiar ways. Matter and energy exist in discrete bits, or quanta: indivisible particles of matter, indivisible quanta of energy. They require quantized rather than continuous spacetime. Trying to fit them in continuous spacetime is like trying to cross a river by riding a bicycle over stepping stones. It’s okay if they’re at the right spacing, otherwise you’re in the water