theorymust depend on practical

As one of my teacher (Bob Hammakker from Kansas State University) says to his students:

Theory guides and experiment decides.

theory and practice are the two wings of fact.

K.U.Sadek

Theory gives the direction and practical gives the results

Theories come and go. Many well accepted theories of past have fallen to disrepute or have lost its significance. Experiments are facts that give the necessary support to the theory. All the theories can be placed in two categories:

1. where experiments can be designed to support it and

2. where no experiment can be designed that opposes it. In either case it is experiment that save any theory.