Why does Advanced Filter require named parameters?

[Glory]

[COLOR=darkgreen]Range("A1:A1000").AdvancedFilter Action:=xlFilterCopy, CopyToRange:=Range("E2"), Unique:=True[/COLOR]

[COLOR=red]Range("A1:A1000").AdvancedFilter(xlFilterCopy, Range("E2"), True)[/COLOR]

Red fails, green succeeds. But I don't understand why it's necessary to specifically name the parameters, when it's normally possible to simply type in arguments.

 

[Norie]

If you don't use named arguments then the arguments need to be in the right position in the list.
So you have to do something to take into account any missing arguments.
Usually that just means adding an extra comma.

 

[Glory]

I guess that includes arguments that are exclusive? Like with advanced filter, you wouldn't do copytorange if you were having it sort in place. But you still need to have a comma to delimit the position of the argument in the list?