Since the applicant has not adequately responded to this concern, his claim that…is untenable.

Nor does the mere fact that…lends significant support to…

Since the editorial fails to rule out these and other possible explanations for …, I cannot accept any conclusions about …

But, since the editorial provides no evidence to substantiate this assumption it is equally possible that …

Thus, without better evidence that …, the editorial remains unconvincing.

Even if the dean can substantiate all of the foregoing assumptions, the dean’s assertion that … is still unwarranted.

It is entirely possible that people inclined to recycle were not willing to respond to the survey than other people were.

Without eliminating this possibility, the owner cannot rely on the national survey to conclude that …

Give these possible scenarios, the fact that…proves nothing about…

By relying on the national survey to support its conclusion the argument depends on the assumption that…

This scenario is quite possible, especially considering that…

Any of these scenarios, if true, would cast considerable doubt on the argument’s conclusion that…