I don&#x27;t think FPLs by themselves are (Turing) tar pits. On the other hand, there are lambda-calculus tar pits - for example SKI combinators. This shows that even a language that has referential transparency and lazy evaluation can be a tar pit; so these qualities by themselves are not a way to avoid complexity.<p>I hope one day we will be able to mathematically formulate what is &quot;unnecessary complexity&quot;.. but so far, no idea.