In many Lisps (+ + +) means this: call the function named + on the two values from the variables named +. The function is then a function object and the values

In many Lisps (+ + +) means this: call the function named + on the two values from the variables named +. The function is then a function object and the values of + can be anything they are currently set to. Thus + serves more than one purpose: function or variable and both may be different values. Thus the position actually matters. What we have below the Lisp syntax are s-expressions: nested lists of symbols and other objects. In s-expressions, symbols need to be separated by whitespace, parentheses or possibly by some special character type (-> terminating character). Characters like +, -, /, *, _, ... are valid characters for any symbols. Thus Lisp does not require functions to be separated by characters but symbols. That's a part of the reader mechanism for reading s-expressions (-> symbolic expression).