argument 48的攻击点选取问题

yingmianboboUID: 2997634

看了坛子里很多的文章与论文，觉得有一点想和大家探讨一下。
Argument48:
The following appeared in a newspaper article published in the country of Corpora.
'Twenty years ago, one half of all citizens in Corpora met the standards for adequate physical fitness as then defined by the national advisory board on physical fitness. Today, the board says that only one quarter of all citizens are adequately fit and suggests that spending too much time using computers may be the reason. But since overall fitness levels are highest in regions of Corpora where levels of computer ownership are also highest, it is clear that using computers has not made citizens less physically fit. Instead, as shown by this year's unusually low expenditures on fitness-related products and services, the recent decline in the economy is most likely the cause, and fitness levels will improve when the economy does.'

因为无数的人都攻击了C市的体质到底有没有下降（包括那篇经典的推荐文）；但是事实上作者没有在攻击这一点（个人意见），因此是否要对这个作者潜意识里面的认为是正确的（也就是整个文章的基础），但是却不属于作者反驳的逻辑链的点进行攻击，有点疑问。

yingmianboboUID: 2997634

2# 大白鲨

恩。。作者默认为C市的人体质下降了。。这的确有点问题。。。但是作者攻击的不是这一点。。。他攻击的是后面的原因。。
我们要探究的是作者的line of reasoning吧。。。
于是我就纠结在要不要攻击作者没有攻击的假想前提。。。

现在想想是可以攻击的了。。。毕竟这是前提。。
但我觉得这与一般的推理argu有点区别。。。这是反驳文。。所以我们应该关心的是作者的攻击。。

PS。。我已经 绕死了。。