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Mastering Unstated Assumptions

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    Mastering Unstated Assumptions

    Dear Mr Cothran,
    I am an adult student who did not have the benefit of a Classical Education; in addition, I am foreigner who learned English as an adult. I was studying for the LSAT (law school admission exam) and failing miserably. I could not understand conditional reasoning. Fortunately, I came across your books: Traditional Logic I and II. I sat down for 3 days straight and covered all the DVDs. I can't tell you how much I have learned and improved. I am so grateful. Thank you so very much. I do have a question. I am struggling with questions that involve assumptions. You cover implicit (unstated) assumptions in chapter 6 of the second book (Enthymemes). However, the arguments in the LSAT are very complex and I am having trouble identifying the unstated premise (see sample below).

    Do you happen to know a good resource to study assumptions and more specifically implicit/unstated assumptions?
    Do you have any helpful resources that I could purchase from Memoria Press?
    Maybe you are familiar with a teacher on the west coast with expertise in this subject matter? I live in CA (between LA and San Diego)

    You have no idea how grateful I am. I am going to purchase the book on material logic as well as the one about rhetoric. Also, I am disseminating your wonderful materials with all my friends and relatives.
    Many, many thanks in advance for your kind response.

    God bless you.

    LSAT sample assumption question:
    Caffeine can kill or inhibit the growth of the larvae of several species of insects. One recent experiment showed that tobacco hornworm larvae die when they ingest a preparation that consists, in part of finely powdered tea leaves, which contain caffeine. This result is evidence for the hypothesis that the presence of non-negligible quantities of caffeine in various parts of many diverse species of plants is not accidental but evolved as a defense for those plants. The argument assumes that ..... ( and then there are 5 choices)


    Do you have the list of possible answers?

    Martin Cothran


      Yes, Mr Cothran. The possible answers are:
      a) caffeine-producing plants are an important raw material in the manufacture of commercial insecticides
      b) caffeine is stored in leaves and other parts of caffeine-producing plants in concentrations roughly equal to the caffeine concentration of the preparation fed to the tobacco hornworm larvae
      c) caffeine-producing plants grow whenever insect larvae pose a major threat to the anscestors of those plants
      d) the tobacco plant is among the plants species that produce caffeine for their own defense
      e) caffeine-producing plants or their ancestors have at some time been subject to being fed upon by creatures sensitive to caffeine.

      The correct answer is e

      Thank you



        Yes, this is what I thought. Tests like this are largely dependent on the process of elimination. You simply set aside the obviously erroneous answers, leaving the one that is the only one that makes any sense. This is slightly different than the process of deriving the missing premise in an enthymeme, although practicing this latter skill will help you to think in a way that make the process of elimination procedure a little smoother.

        I would recommend that, if you have already done my course, you simply drill the procedures like process of elimination that are discussed in the preparation manuals for the LSAT. These tests have certain set approaches and if your goal is simply to do well on them, then a general knowledge of logic from doing something like my book and a specific knowledge of the kinds of questions they ask and specific strategies for answering them is the best way to prepare.

        Mr. Cothran


          Thank you very much. Your books have been tremendously helpful already. ALL questions on the LSAT seem a lot easier I will keep practicing. On a related note, I reviewed many books that offered "gimmicks" to answer logic questions. Nothing was as helpful as studying the concepts presented in your books. I am truly grateful.
          Any other books from the Memoria Press series that would supplement my learning and understanding?

          With gratitude,



            You might try Peter Kreeft's Socratic Logic for a more advanced treatment of what is in my books. Also, just reading St. Thomas Aquinas' Summa Theologica is great mental training.



              Thank you very much! you are fantastic.