Why can't economists agree?

Isn't economics really just a lot of numbers and math? So, why can't economists agree on... just about anything? Ah, well, yes, maybe there is a lot of numbers and math, but there are also a lot of assumptions behind that math and a lot of interpretation of the numbers and the mathematical results and subjective values on those interpretations. In fact, it is all such a mess that economists refer to "schools of economic thought", which basic means groups of people who can't with other groups of people. The Wikipedia gives us this list of 27 schools of economic thought (and more!):

1. Ancient economic thought
2. Islamic economics
3. Scholasticism
4. Mercantilism
5. Physiocrats
6. Classical political economy
7. American (National) School
8. French liberal school
9. German historical school
10. English historical school
11. French historical school
12. Utopian economics
13. Marxian economics
14. State socialism
15. Ricardian socialism
16. Anarchist economics
17. Distributism
18. Institutional economics
19. New institutional economics
20. Neoclassical economics
21. Lausanne school
22. Austrian school
23. Stockholm school
24. Keynesian economics
25. Chicago school
26. Carnegie school
27. Neo-Ricardianism
28. Modern schools
29. Current heterodox schools
30. Other 20th century schools
31. Viewpoints within mainstream economics
32. Viewpoints outside economics

Even to get agreement between the prominent Chicago, Austrian, and Keynesian schools  would be difficult enough, but we have so many diverse views on so many of the factors that influence how the basic numbers and math of economics are interpreted. Even for seemingly simply issues such as the role of government in commerce.

 

-- Jack Krupansky