There are two kinds of economics - scientific so-called micro economics, and pseudoscientific macro economics. Stuff like Keynes and the Philips Curve falls into the latter category.
Macro economics is "scientific" to the extent that it allows the elites to cloak their power-grabbing (and money-grabbing, which comes to pretty much the same thing) in the mantle of "science."
Which is pretty much the same reasoning that makes man-made global warming "scientific."
Capitalism is un-scientific, you see. If you want to be scientific, you have to put away all that, and move on to socialism, which is totally scientific.