Twenty years ago, Dr. Field, a noted anthropologist, visited the island of Tertia. Using an observation-centered approach to studying Tertian culture, he concluded from his observations that children in Tertia were reared by an entire village rather than

The argument that Dr Field's conclusion about child-rearing in Tertia is invalid and that children are reared by their own biological parents ignores several assumptions that are crucial for the statement.

First, the argument assumes that all islands in the group have a similar culture and that the overall conclusions can be applied for the island of Tertia individually. It is not mentioned whether children of Tertia specifically spent more time talking about their biological parents or not. The possibility of child-rearing practices in Tertia being different from practices in the other islands is never considered. In such case, no conclusion about Tertia could be drawn from a general study in the group.

Second, the argument considers that the only reason children would speak more about their biological parents is because they were reared only by them. It is not considered that they might have a special relationship with their biological parents despite being raised by the entire village. As the author does not mention what the kids said about their parents, we cannot conclude that they were raised by them solely from this information.

Finally, it assumes that nothing changed in the twenty years that passed between the two researches. It is possible that in this period there were changes to the culture of the village and that the conclusion of Dr. Field was valid then but no longer applies. In this case, Dr. Karp is right to assume that children are raised by their biological parents, but cannot invalidate Dr. Field conclusion nor assume that an interview-centered approach is more efficient than an observation-centered one to avaliate child-rearing practices, as both studies reached the right conclusion.

Clearly, the argument is based on unsubstantiated assumptions that invalidate the conclusion. The evidence provided to support that children in Tertia are reared by their own biological parents does not addresses the points previously mentioned and therefore does little to prove the conclusion. The argument might be strenghtened if the author could provide additional support for his assumptions.