Critical Reasoning

Within 20 years it will probably be possible to identify the genetic susceptibility an individual may have toward any particular disease. Eventually, effective strategies will be discovered to counteract each such susceptibility. Once these effective strategies are found, therefore, the people who follow them will never get sick.

The argument above is based on which of the following assumptions?

C. All human sicknesses are in part the result of individuals' genetic susceptibility
D. All humans are genetically susceptible to some diseases.

Out of these two option, C is the best answer, because the arguement is about human sickness, not about human. So, D becomes out of scope.

Please post all five options.

Cheers

out of these 2 , D is better but I don't know whether that will be the best out of the lot.

All the options pl.

C +1

Conclusion: the people who follow them(effective strategies) will never get sick.

But effective strategies are developed only for susceptible diseases. So if a person only gets diseases to which he/she is susceptible then the conclusion is true.

So the inherent assumption for conclusion to be true is: a person only gets diseases to which he/she is susceptible

Option C represents the same assumption in different words.

Between C and D, C is better; however there is a loophole in C.

It says all sickness in PART, so there is another part of the sickness also which may not be Genetic. SO Humnas can still get sick even after genetic disabilities are removed. What do you guys think?

Choice C is definitely correct, and amit and electrico's reasonings seem to be on the right track.

The evidence establishes that within 20 years all genetic susceptibilities will probably be identified, and that eventually there will be strategies in place that counteract all of these susceptibilities.

The conclusion is that once the strategies are found, people who follow them will NEVER get sick.

Note the extremity of the conclusion. He's saying people will never get sick.

Well, that's only true if people never get sick from diseases for which they do not have a genetic susceptibility. In other words, the author is assuming that all sicknesses are linked to a genetic susceptibility.

Choice C matches this prediction.

________________

Because this is a necessary assumption question, we can also use the Kaplan denial test.

Choice C reads:

"All human sicknesses are in part the result of individuals' genetic susceptibility."

whose denial would be:

"Not all human sicknesses are in part the result of individuals' genetic susceptibility"

which we can rephrase as:

"Only some human sicknesses are in part the result of individuals' genetic susceptibility"

in which case the argument that people will NEVER get sick falls apart.

Thus, choice C represents an assumption on which the argument is "based".

The author's argument does not commit him to assuming choice D. If we deny choice D we have:

"only some humans are genetically susceptible to (some) diseases"

to which the author could rightly respond:

"who cares? If some people don't ever have to worry about getting sick, then fine. However, for those who do, soon they won't ever get sick if they follow the strategies (once such strategies are found)."

The argument can still stand even after denying choice D. Thus, choice D is not an assumption on which the argument is based. Or, in other words, choice D is outside the scope of the author's argument.

testluv,

everthing else looks ok but I have just one question.

choice C states "All human sicknesses are in part the result of individuals' genetic susceptibility "

so if we find a solution to the gene related thing , then also there is a possibility that the person might fall sick as there would be some other factor which might act upon to cause disease.

Pl. explain.

ansumania wrote:testluv,

everthing else looks ok but I have just one question.

choice C states "All human sicknesses are in part the result of individuals' genetic susceptibility "

so if we find a solution to the gene related thing , then also there is a possibility that the person might fall sick as there would be some other factor which might act upon to cause disease.

Pl. explain.

Yes. Choice C is necessary but not sufficient for the argument to stand. In order for the argument to stand, the author HAS to assume that all human sicknesses are at least partially linked to genetic susceptibility. Now, this won't necesarily guarantee that the argument will stand--but this premise is necessary for the reasoning.

hi,

thanks for the reply..

Pl. tell me this: how do we negate a statement

for e,g: option C could be negated in two ways

1-Only some human sicknesses are in part the result of individuals' genetic susceptibility

2- all human sicknesses are totally the result of individuals' genetic susceptibility

how to know which part to be logically changed in order to get the negated statement?

how to know which part to be logically changed in order to get the negated statement?

Terrific question!

A common mistake is to think that we can negate wherever it is grammtically possible to do so (ie, whereever it is grammtically possible to add (or remove) a "not").

However, that is not true, for then there would be multiple possible negations. And yet because the answer choice means only ONE thing, so too there can only be ONE proper negation of that statement.

So, how do you know where to negate a statement?

You have to think about what the statement means. Then, you have to deny the statement's meaning.

So, for choice C, this:

"Not all humans are in part the result of individuals' genetic susceptibility"

is the proper denial but this:

"All human sicknesses are not in part the result of...."

is not. (One way to see this is that the second negation is ambiguous: if humans sicknesses are not in part the result of genetic susceptibility, does this mean that they are not at all linked to genetic susceptibility or that they are completely (not in part) linked to genetic susceptibility? Whereas the first negation clearly negates the meaning of the statement. Another way to see it: the first but not the second negation operates on the subject of the sentence.)