Here we have a strengthen with necessary premise question. Remember that a premise is necessary for a conclusion if the falsity of the premise guarantees or brings about the falsity of the conclusion. First we check to see if the answer choice strengthens the passage, and then, if it does strengthen, we negate the answer choice to see if its negation makes the argument fall apart. If the answer choice does both those things then it is our correct answer.
Conclusion: "serendipity can no longer play a role in scientific discovery."
Why? We know that many major discoveries of the past were the product of serendipity--the chance discovery of valuable findings that investigators had not purposely sought. However, we know that currently scientific research tends to be so costly that investigators are very dependent on large grants to fund their research. These grants require investigators to provide grant sponsors with clear projections of the outcome of the proposed research. So, investigators ignore proposals that do not directly bear on the funded research.
But, have we been given any info one why findings that an investigator had not purposely sought out, i.e. serendipitous findings, cannot play a role in scientific discovery? No. Thus, our correct answer must help us bridge these two things.
Answer choice (A) does just that.
Does answer choice (A) strengthen? Yes.
We are given a reason as to why serendipitous findings cannot play a role, i.e. directly bear on one's research. We are told that if it directly bears on that investigator's research, then it was a finding that the investigator purposely sought out.
(A): DB ==> PS not PS ==> not DB
As you can see, the contrapositive of (A) tells us that if it was not purposely sought out, i.e. if it was serendipitous, then it does not directly bear on that investigator's research. Therefore, answer choice (A) strengthens the argument because it helps us infer the conclusion.
Does the negation of answer choice (A) make the argument fall apart? Yes.
We are told point-blank that it is not just those findings that are not serendipitous that directly bear on the investigator's research. Therefore, it no longer stands that serendipity cannot play a role in scientific discovery.
If you have any specific questions on any of the other answer choices, please feel free to clarify.
Hope that clears things up! Please let us know if you have any other questions.
AnkitMFebruary 23, 2016
I'm confused, hope you can clarify a bit. Is negating the same thing as finding the contrapositive? Contrapositive of DB -> FPS (not FPS -> not DB), would not be the same as the negation right? So the negation would be "only findings that an investigator purposely seeks CANNOT directly bear on that investigators research." So it would be (not DB -> FPS). Thanks in advance.
MehranFebruary 23, 2016
@AnkitM the contrapositive requires you to reverse and negate so while negation is part of the contrapositive it is not the same thing.
Remember, negation is the minimum required to disprove a statement.
Let's take a look at a simple example first:
All apples are red.
A âž¡ï¸ R
not R âž¡ not A
How would you disprove this statement? You would show me a green apple.
Notice what that does. You are giving me the sufficient condition (i.e. apple), but showing that the necessary condition is not necessarily present.
So the negation of "All apples are red" would be:
A âž¡ not R
Now let's take a look at (A).
We know "only" by itself introduces a necessary condition so (A) would be diagrammed as follows:
DBIR âž¡ï¸ FIPS
not FIPS âž¡ï¸ not DBIR
How would I negate this? By showing sufficient without necessary (i.e. some things that directly bear on research are NOT findings that an investigator purposely seeks):
DBIR âž¡ï¸ not FIPS
For a more in-depth discussion on this topic, please re-watch our lesson on Statement Negation in our Strengthen lesson.
Hope this helps! Please let us know if you have any other questions.
