Yes but, as you’ll come to realize, SyntaxErrors confuse the interpreter.
In this case the “unexpected comma” (and 2nd argument,) is not the cause of the SyntaxError it’s the symptom.
The main error in your syntax was confusing the interpreter by separating an identifier (with a space) and what the interpreter thought was an expression enclosed in parenthesis.
In the first use, with a single argument, the expression in parenthesis was evaluated to the array disney_movies and that result passed to the method as a single argument.
But when the comma and another expression true was added, Ruby did not know how to evaluate what it though was an expression inside parenthesis.
When this space is removed, the interpreter correctly sees a method call with multiple arguments instead of a reference identifier and a separate expression.
If you had omitted the parenthesis, Ruby would not have been confused. Ie …
puts "In backwards sort: #{sortedlist disney_movies, true}"
… should have worked. (But most style guides are against method calls that do not wrap the parameter lists in parenthesis.)
But I would suggest you read the “Pick Axe” book.
It is listed in my book list in the Ruby Resources lists.