There absolutely are real phenomenon in economics. There are none in astrology that have been proven.

But from the perspective of earth, there are times when Mercury appears to reverse its course. The other planets do it too

But that’s not astrology. Astrology is the art of giving it mysterious meanings. Mercury being in retrograde is an astronomical phenomenon.

The problem with economics is that it’s essentially sociology and you obviously can’t make absolute laws about things that involve people. But I’ll give you two simple examples that absolutely have been proven time and time again:

1. Induced demand - if you make something more available (cheaper), that in of itself is usually enough to make demand for it higher.

2. Inelastic demand - if something is an absolute necessity then it becoming more expensive doesn’t reduce demand to 0 (healthcare, fuel).

#2, incidentally, is one reason why markets will never be truly efficient and need to be regulated. The equilibrium of supply and demand can’t be what determines the price of healthcare, transportation, etc.

Economics blows up when you try to make things absolute rules, or when you try to rationalize markets that have people with tons of money FOMOing bullshit based on marketing. Two problems come to mind:

1. The P/E ratio of 10 is stated as a rule in investing, but there’s no reason that’s the exact right amount, it’s really just something that on average, people buying stocks find a sensible return rate because similar rates could be achieved elsewhere too.

2. Conversely to the last point, people marketing IPOs for companies making zero profit will convince you that really horrible P/E is fine because those companies will take over the entire global market for whatever. See, that’d be true IFF there’s a market AND they remain the biggest player. Just because a P/E ratio of 10 being optimal isn’t an absolute law of the universe doesn’t mean a P/E ratio of 1000 is any good.