If we would follow the arguments of ID-skeptics we would end up denying the existence of human intelligence and design.
First establish what it means to design, what the minimal requirements are to call something intelligence or design, what intelligence means with humans as an example, then see if you can apply the established meanings of intelligence and design in a broader context then human design. This will neccessarily be seen to be the case, since the events in a human brain are not absolutely different then events elsewhere in the universe. They are comparative.
regards,
Mohammad Nor Syamsu