I think that is because method is already defined as a Method....
Merlin:~/rails cbeck$ irb irb(main):001:0> d = 1 => 1 irb(main):002:0> d.methods => ["to_a", "%", "<<", "respond_to?", ">>", "divmod", "&", "type", "integer?", "chr", "protected_methods", "eql?", "to_sym", "*", "instance_variable_set", "+", "is_a?", "truncate", "hash", "send", "to_s", "-", "between?", "modulo", "singleton_method_added", "prec", "zero?", "/", "size", "class", "tainted?", "private_methods", "__send__", "next", "|", "untaint", "id", "~", "step", "to_i", "inspect", "instance_eval", "prec_i", "remainder", "clone", "nonzero?", "public_methods", "^", "+@", "floor", "extend", "freeze", "-@", "**", "quo", "display", "__id__", "<=>", "downto", "to_f", "<", "method", "methods", "==", "===", "prec_f", "abs", ">", "to_int", "nil?", "dup", "instance_variables", "coerce", ">=", "instance_of?", "ceil", "<=", "upto", "div", "times", "object_id", "=~", "singleton_methods", "equal?", "succ", "taint", "id2name", "", "frozen?", "instance_variable_get", "kind_of?", "round"] irb(main):003:0> d.method ArgumentError: wrong number of arguments (0 for 1) from (irb):3:in `method' from (irb):3 irb(main):004:0>
I'm not sure of the intricacies of rails but this would be my guess.
