CC: 19 Common Argument Flaws - "Beliefs vs Facts"

JerseyRhk3JerseyRhk3 Alum Member
edited February 2017 in Logical Reasoning 114 karma

Hello all,

I’m seeking some clarification for the following argument that is given as an example of a “Belief vs Facts” flaw in the Core Curriculum.

Admin edit: Removed. Please link to the argument and do not post things directly from the course.

My breakdown of the argument is as follows:
A (FRB) is a (X)
Dr. L knows that her colleague’s lab detected a (FRB) earlier this year
Therefore, Dr. L knows that her colleagues lab detected an (X)

The curriculum says the conclusion does not follow because it’s not clear that Dr. L knows what (X) is, except that her colleague’s lab detected one. So my question is would the conclusion follow if it instead said “Therefore, Dr. L knows that her colleague’s lab detected a (FRB)”, rather than an (X) that was erroneously concluded? I’m just a little tripped up because the argument is concluding that Dr. L knows that her colleague’s lab detected something (X), which follows from the premise that Dr. L knows that her colleagues lab detected an (FRB), which is an (X). I feel as though my lack of understanding for this flaw is exploited time and time again on LR questions so any additional insight is appreciated. Thanks!

Comments

  • Jonathan WangJonathan Wang Yearly Sage ⭐
    edited February 2017 6869 karma

    Let's say you and I are researchers. After months of research and experiments, we've just come up with conclusive evidence that any person who takes the LSAT turns into an insufferable human being within five years. At this time, we're the only two people who know the results of our research.

    Now, say we have a friend. Let's call him Warren. Warren knows that his girlfriend Sally has just taken the LSAT. Can we then conclude that he knows that she will turn into an insufferable human being within five years, and that he should probably break up with her before it's too late?

    I mean, WE know that. But does he?

    Apply to Dr. L. Dr. L knows that her colleague's lab detected an FRB. To say that she therefore must know that her colleagues' lab detected an (X), you are assuming that she knows that FRB and (X) are connected, just like you're assuming that Warren knows that the LSAT and being an insufferable person are connected. Can we do that?

    Hope this helps.

  • BenjaminSFBenjaminSF Alum Member Inactive ⭐
    edited February 2017 457 karma

    I think the part of this argument that makes it tricky is that the author uses an example that has a subtle assumption about the knowledge possessed by Dr. L. We take for granted that because Dr. L knows what FRB is, that she must also be aware that X exists and has a relationship to FRB.

    Here's the more blatant example I used to parse this out for myself:

    Today, we know mermaids spotted by sailors were actually manatees.

    Let's suppose in 1730, Dr. L's first mate spied a mermaid off the starboard deck of their science vessel.

    Dr. L knows that her matey saw a mermaid.

    Can we therefore say that she knows that her matey saw a manatee? No. We know that Dr. L is aware of what a mermaid is, but we don't even know if she is familiar with the manatee yet. It is also possible that she knows of the manatee, but she is not aware that the mermaid and manatee are one and the same.

    This applies to the FRB and X in the same way. We are told that FRB is a X. We know this in the present. Earlier this year, Dr. L learns about her colleague's FRB. Does that mean she is even aware of X? It could be that it was only discovered after this event occurred. It is also possible the she knows of X, but she is not aware that it is the same as FRB.

  • JerseyRhk3JerseyRhk3 Alum Member
    114 karma

    This makes much more sense. Thanks guys @"Jonathan Wang" @BenjaminSF

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