Although it is sometimes claimed that consuming caffeine at high level

Although it is sometimes claimed that consuming caffeine at high levels does not cause insomnia, statistical evidence shows that it does. Study after study has found that people with high levels of caffeine consumption from beverages such as coffee, tea, and soft drinks are far more likely to suffer from insomnia than people who consume little or no caffeine.

The conclusion of the argument is the following:

statistical evidence shows that it (consuming caffeine at high levels) does (cause insomnia)

The support for the conclusion is the following:

Study after study has found that people with high levels of caffeine consumption from beverages such as coffee, tea, and soft drinks are far more likely to suffer from insomnia than people who consume little or no caffeine.

We see that the author has reasoned that, since studies have shown that people with high levels of caffeine consumption are more likely than others to suffer from insomnia, evidence shows that consuming caffeine does cause insomnia.

In other words, basically, the author has seen a correlation between caffeine consumption and insomnia and concluded that caffeine consumption causes insomnia.

Which of the following is an assumption on which the argument depends?

The correct answer will state an unstated assumption that is required for the evidence to support the conclusion.

A. Caffeine consumption is the only commonly occurring cause of insomnia.

People sometimes choose this choice because they've heard that one common assumption in a cause-effect argument is that there is not an alternative cause for the effect. So, in this case, we might think that the argument depends on the assumption that caffeine consumption is the only cause, meaning that there is not an alternative cause for insomnia.

However, in this case, the conclusion is not that caffeine consumption is THE ONLY cause of insomnia. It's essentially that caffeine consumption is A cause of insomnia.

Arriving at that conclusion doesn't require the assumption that caffeine consumption is the only cause. After all, even if there are other causes, it could still be the case that caffeine consumption causes insomnia.

Eliminate.

B. Consumption of high levels of caffeine is not itself a result of something that causes insomnia.

In the argument, the conclusion that statistical evidence shows that consuming caffeine at high levels does cause insomnia is based on the evidence of a correlation between consumption of caffeine at high levels and insomnia.

In going from that evidence to the conclusion, the argument depends on the assumption that there's not some other reason for that correlation.

One possible other reason for the correlation is that something else causes both consumption of high levels of caffeine and insomnia.

So, in going from the evidence involving a correlation between consumption of high levels of caffeine and insomnia to the conclusion that statistical evidence shows that consuming caffeine at high levels does cause insomnia, the author is assuming that, as this choice says, it's not the case that consumption of high levels of caffeine is itself a result of something that causes insomnia.

Keep.

C. Anyone who regularly consumes caffeine in more than moderate quantities will suffer from insomnia.

Notice that the conclusion is that statistical evidence shows that consuming caffeine at high levels DOES cause insomnia. It's not that consuming caffeine at high levels ALWAYS causes insomnia.

It could be that consuming caffeine does cause insomnia even if it does not always cause insomnia.

So, the argument does not depend on what this choice says since the argument still works even if not everyone who regularly consumes caffeine in more than moderate quantities will suffer from insomnia.

Eliminate.

D. The only evidence available to show whether caffeine consumption causes insomnia is statistical evidence showing correlations between caffeine consumption and insomnia.

The argument uses evidence showing correlations between caffeine consumption and insomnia. At the same time, the fact that the argument uses such evidence does not mean that the argument would not work if that evidence is not "the only evidence available to show whether caffeine consumption causes insomnia." After all, even if there is other evidence, the argument could still work. In fact, such other evidence might provide even more support for the conclusion.

Notice that this choice doesn't say, "There is no evidence available that shows that caffeine consumption does not cause insomnia." So, we can't assume that what this choice implies is that, if statistical evidence showing correlations between caffeine consumption and insomnia is not the only evidence that shows whether that caffeine consumption causes insomnia, then the other evidence shows that caffeine consumption does not cause insomnia. Other evidence could provide additional support for the conclusion.

Eliminate.

E. Consumption of caffeine from sources other than coffee, tea, and soft drinks is unlikely to cause insomnia.

The conclusion is based on the fact that people with high levels of caffeine consumption from beverages such as coffee, tea, and soft drinks are far more likely to suffer from insomnia than others.

However, the conclusion is not that only caffeine from those beverages causes insomnia. It's that caffeine consumption in general causes insomnia.

So, the argument works even if consumption of caffeine from sources other than coffee, tea, and soft drinks is NOT unlikely but, rather, likely to cause insomnia.

Eliminate.

Correct Answer