I would agree more with this view if there was also an explicit indicator for lazyness: in (define (foo arg1 arg2) (+ arg1 arg2)) the two parts (foo arg1 arg2)

I would agree more with this view if there was also an explicit indicator for lazyness: in (define (foo arg1 arg2) (+ arg1 arg2)) the two parts (foo arg1 arg2) and (+ arg1 arg2) are both interpreted specially; the former as a data structure and the latter as code with delayed execution.