Statistics today can answer the question of causality in many cases, especially the controlled studies, and that use to be the domain of philosophy.
Statistical decision theory also supercedes many philosophical problems.
A number of lesswrong articles, typically addressing the nature of categories and how to reason based on them, also move into this territory and browsing lesswrong is probably worthwhile if you are interested.
To summarize, for those who don't want to archive-dive LW:
Analytic philosophy has traditionally held that concepts/categories are logical: defined by a conjunction or disjunction of predicates in a formal language. Or at least, it holds that they ought to be once we stop being silly and think clearly.
Most everything we've ever learned in machine-learning and cognitive science instead tell us that concepts/categories are statistical, and that formal logic is therefore not only a brittle framework for real-world reasoning but thoroughly incapable of describing where its own constituent objects come from in the mind.
I'm not saying we sholdn't do philosophy because it can be dangerous. Philosophy can also be very good. In fact, we need the good ideas to prove the bad ideas wrong. I am a big fan of philosophy.
But not at the point of a gun (i.e., not on the taxpayer's dime). Philosophers used to be self-funded or funded by patrons. As an aside, since philosophers have become primarily funded by governments and guns, we have a 10,000 fold increase in the number of philosophers, and no increase in the quality of output.
I don't know that for certain, maybe he's just actually curious, that's why I just answered his question instead of saying this to him.
Many people think of communism when they hear the word "Marx". Few have read his arguments.
Of course, someone who quotes Objectivism in their profile is not in a strong position to talk about philosophy ;)
The open question is if government with checks and balances is stable in the long term, or if it will fall apart and have one branch take over. Time will tell.
Second, Marx made Stalin possible by setting up the necessary intellectual framework of class struggle, capitalism as oppressive, dialectical materialism (denial of reason and free will), etc.
I'm uncomfortable attributing Marx to philosophy entirely...like many historical figures it seems like he's only a partial fit. Just pointing out where your reasons leads.
Even so Analytic Philosophy was just a reaction against British Hegelians in the later 19th century, starting with Bertrand Russell. Those distinctions get thrown around way too crudely.
Also, Dan Brown sells like crazy and is easy to read. Zizek, no one can read, and no one actually buys his books AFAIK. But at the level of 'sensationalism' perhaps I could see that.
It's like someone who has only ever seen click bait dismissing journalism as pointless.