Logical Reasoning

PT131 · S1 · Q15 The typological theory of species

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The typological theory of species classification, which has few adherents today, distinguishes species solely on the basis of observable physical characteristics, such as plumage color, adult size, or dental structure.

Opposing Point

The typological theory of species classification, which has few adherents today, distinguishes species solely on the basis of observable physical characteristics, such as plumage color, adult size, or dental structure.

Premises (since)

However, there are many so-called “sibling species,” which are indistinguishable on the basis of their appearance but cannot interbreed and thus, according to the mainstream biological theory of species classification, are separate species.

The typological theory does not count sibling species as separate species.

Conclusion

The typological theory is unacceptable.

Evaluate

The argument assumes that sibling species should be counted as separate species. That the mainstream biological theory views sibling species to be separate species does not establish that they are.

15.

The reasoning in the argument is most vulnerable to criticism on the grounds that

  1. the argument does not evaluate

    Not a Flaw

    In order to undermine the typological theory, the argument does not need to evaluate all aspects of the typological theory, but rather those aspects which are wrong.

    2% picked this

  2. the argument confuses a necessary

    Wrong Flaw

    This common LSAT flaw is not present in this argument. This reasoning structure is not conditional logic, but rather comparison.

    8% picked this

  3. Correct

    the argument, in its attempt

    Why this is right

    This presents an assumption of the argument.

    Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

    46% picked this

  4. the argument takes a single

    Not a Flaw

    A single fact that is incompatible with a theory is enough to show that theory to be false.

    44% picked this

  5. the argument does not explain

    Not a Flaw

    The argument does not need to explain why sibling species cannot interbreed.

    1% picked this

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