That doesn't make it invalid. There are other ways to discover truth; eg, reasoning, mathematical proof, or detective work. The latter applies the knowledge gained from science, but the crime itself isn't repeatable.
Then again, given how divided economists are on basic questions, there must be a lot of blarney in the field.
I actually don't think repeatable experiments is a necessary characteristic of science. I would argue that science is more about generating falsifiable hypotheses that can be tested through some method, whether through repeatable experimentation or through observation (what you call detective work).
There really isn't that much disagreement. Just alot of pundits masquerading as economists (who may have an undergrad degree) who use 'economics' to justify their absurd political idealism.
If you ask economists who actually make a difference (central bank economists, investment bank strategists), and make decisions that actually affect people, I bet there'd be alot more agreement.
Of course, disagreement in a field has nothing to do with the validity or science like nature of the field itself. Consider, for example, the disagreements between Gould and Dawkins in the field of biology. Does this mean biology is not a science?
I'm also sure that you'd find even more agreement between say, Ben Bernanke and Mark Carney.
A lot of psychology, for example, rests on experiments run on 19-year old college sophomores in Western countries. Are these actually universal human traits, or do they change depending on cultural trends?
True.