I do not deserve to call neoclassical economics into question that it may be designed to support for capitalist. Even I am not sure for myself to be free from the question. When I read Marx, frequently I find I am close to the guys who are criticized by Marx. Aside this tough philosophical question, still there is a test that economics as science should pass. It is reality .
Science starts and ends with reality.
Otherwise saying, its assumptions for abstract should be tested for their validity and its result should be certified by empirical observations. While neoclassical economics starts with assumptions of utility that is neither observable nor measurable, it can never pass the test for science no matter whether it may look nice in its theoretic deduction and offer a wonderful implication on economy. If a theory neglects to test assumptions and just emphasizes its conclusion, the theory has more chances to become a dogma. Above three based on almost the same model in them.