There is no other way to do it. Imagine for example you are trying to prove that 2 plus 2 is 4. You at first have worked out a mathematical model that this is so, and then you go to the real world to push 2 sets of chairs together and see that you derive 4.

Now, when a psychologist comes up with an idea about human behavior, first he makes a hypothesis, or a theoretical model, than he goes on to apply it to the real world.

Quite simply, it is not possible to pursue the truth without first having a hypothesis or internally thinking through.