cognitive psychology. PhD 
If you’re ever unsure what functional programming means, just remember—John Backus unambiguously declared that the lambda calculus (and presumably its descendants, like Haskell) is NOT functional programming.
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“Lambda calculus depends on substitution rules that are simply stated but whose implications are difficult to comprehend. The true complexity of these rules is not widely recognized but is evidenced by the “proofs” of Church-Rosser that failed to account for these complexities.”
