Mathematical laws are somewhere in between: they are often arbitrary and unproven in themselves, but they are sometimes judged by how useful they are in making predictions about the real world.
[1] Philosophers such as Lee McIntyre are optimistic that "law-like" explanations of human behavior can be valid and useful.
Marxism criticized the belief in eternal laws of economics, which it considered a product of the dominant ideology.
With the advent, in the 20th century, of the application of mathematical, statistical, and experimental techniques to economics, economic theory matured into a corpus of knowledge rooted in the scientific method rather than in philosophical argument.
Finally, the term is sometimes applied to less rigorous ideas that may be interesting observations or relationships, practical or ethical guidelines (also called rules of thumb), and even humorous parodies of such laws.