为了帮助大家备考ACT，新东方在线ACT频道整理了《ACT议论文写作之因果论证》，希望对大家有所帮助。

　　因果论证

　　因果论证是比较常见也是大多数同学使用较多的论证方法，但是通常情况下写出的因果论证并不深入。因为原因有时是多层的，有些现象看起来似乎是发生作用的原因，但在它们的背后，却还有产生它们的原因。对于多重原因的事物，如果只停留在其中的某个层面上，把它当成最终因素，论点就可能不深刻，也难以把问题说透。这样的因果论证，其说服力是有限的。

　　遇到这种情况，应当一层一层地追究下去，一直到找出最终极的原因为止。一般来说，越是表层的原因，越是为大家所熟知的，其论证力也就越有限;越深层的原因，就越能说明问题的实质，就越有说服力。

　　以旧版本满分范文Intelligent Machines里面的一段话为例。

　　【例1】

　　The replacement of humans by machines leads to the loss of value to human life, an effect that outweighs the material gains of automation. The search to find human tasks that can be performed by machines inevitably leads to comparisons between the human and the machine. If a company executive wants to see if a inventory management team can be replaced by a robotic system, he will compare the two and determine which can do a better job. When this occurs, the people on the team are evaluated not for their worth as human beings, but for their effectiveness at performing a specific function—in essence, as we would evaluate a machine. In a larger sense, when we begin to think about humans in this way, the worth of a person’s life becomes dependent on only what they can do and no longer has any intrinsic value. As Perspective One states, we begin to lose our humanity. This new mindset and way of evaluating people, though seemingly harmless in the workplace, is devastating when it begins to pervade a society. If a person is judged only on his or her capability, there is no reason for a person to remain after they have served their function. This would warrant genocide against the elderly and the disabled because their burden on society would not be made up for by any production. Although the machines may seem to only fulfill the low skill jobs at the moment, there is no barrier to prevent the machines from replacing more. As the machines increase in intelligence, they will replace any tasks done by humans and render us unnecessary and worthless.

　　这个段落的主题句是The replacement of humans by machines leads to the loss of value to human life.机器代替人类将会使人的生命失去价值。之后运用因果论证方式来详细展开，逻辑关系如下：

　　human tasks be performed by machines

　　comparisons between human and machine

　　a company will compare the two

　　people are evaluated not for their worth as human beings,

　　but for their effectiveness at performing a specific function

　　the worth of a person’s life depends on their capacity

　　person no reason to remain after serving their function

　　genocide against the elderly and the disabled

　　最后作者又论证了genocide产生的原因，也就是their burden on society would not be made up for by any production。从这个论证过程可以看出，作者论证了machines的使用会导致genocide的过程，中间缺少任何一个环节就不能推出最终的结果。

　　通过这个例子我们看到，在运用因果论证的时候，需要注意：

　　1、紧扣文章的论点，突出原因分析与议题、论点结合的紧密性;

　　2、因果论证层层推进，遵循A导致B，B导致C，C导致D的论证方式，中间不能出现逻辑断层，保证逻辑的严谨性和深入性。

　　因果论证的一些常见标志词有哪些呢?

　　文章中出现了如

　　because, warrant, lead to

　　等表示因果关系的词，除此之外，表达因果关系常用的词或短语还有：

　　consequently, thus, result from, originate from, since, thus, therefore, be responsible for等。

　　记住以上这些高频词，会让你的ACT写作论证时更出彩的。