To achieve interstellar travel, the Kline Directive instructs us to be bold, to explore what others have not, to seek what others will not, to change what others dare not. To extend the boundaries of our knowledge, to advocate new methods, techniques and research, to sponsor change not status quo, on 5 fronts:

1. Legal Standing. 2. Safety Awareness. 3. Economic Viability. 4. Theoretical-Empirical Relationship. 5. Technological Feasibility.

We need to note that there are several different relationships between the mathematics of physics and the physics of the real world.

The first relationship and most common type is that several different types of equations in physics describe the same physics of the world. Gravity is a great example. The three mathematical theories on gravity are relativity, quantum and string theories. All three model the same single physical phenomenon, gravitational fields. So if one is correct than the other two must be wrong. All three cannot be correct. So which is it?

Just for argument sake, there is another alternative — all three are wrong. But wait didn’t all those experiments and observations prove that General Relativity is correct? Remember for argument’s sake, that proving that something fits the experimental observation does not mean that is how Nature works. That is why theoretical physicists spend so much time, money and effort considering alternatives like quantum and string theories.