The author claims that the Palean baskets, which was considered as unique to Palea before, were in fact not unique . To support this claim the author points out that although that the Palean baskets had been found in an village across the Brim River, it is impossible and necessary for Paleans to go across the river. The conclusion relies on a series of unsubstantiated assumptions, which considered together render the argument wholly unconvincing.
First of all, the author's conclusion depends on the doubtful assumption that Paleans must go across the river to Lithos. While this might be the case, the letter provides no evidence to support it. It is entirely possible that this river is small and there was already a bridge across the river then. Just as likely, there were other land roads which could connect these two village. Or even, there might be no river between these two villages in ancient time.
The author's conclusion relies on the second assumption that the ancient Paleans could only have crossed the river by boat. Even if it is true that crossing the river is the only means for Paleans to go to Lithos, this will not necessarily be the case. It is entirely possible that Paleans were smart enough then to fabricate a advanced tool to go to the other bank. Moreover, swimming is another good idea for a good swimmer to go across this river. Without ruling out these possibility, it is unreasonable to say that the ancient Paleans could only have crossed the river by boat and to discuss the invention time of boats and cargo is also meaningless.
A final problem involves the assertion that Paleans had no need to cross the river. The author only concerns the need of Paleans across the river in terms of food and fails to account for the possibility that there were every other reasons to make the them crossing the river. Perhaps, Lithos was a ideal place for them to have fun. Or perhaps, the soil there were more fertile than that of Palea. Without ruling out these and all other explanations, the author cannot convince me that it is unnecessary for Paleans to go across to Lithos.
In conclusion, the author's conclusion is unconvincing as it stands. To strengthen it, the author must provide affirmative evidence that it is the unique way for Paleans to go across the Brim River to Lithos , and Paleans then did having no ability and necessity to go across the river.