EXTRACTOS

 
To EXTRACT an argument from a text involves (a) locating the conclusion of the argument, and (if necessary) restating that conclusion in clear, literal terminology. It next involves (b) locating and again (if necessary) restating the central premises from which the conclusion is derived in the passage. It also might involve (c) adding any additional premises required to make the argument valid.
 
To EXPLAIN the argument involves (a) defining all the technical terms that appear in the argument, and (b) giving a rationale for each of the premises of the argument. In some cases, the rationales are clear from the text. In other cases, the extractor must "read between the lines", and figure out what probably motivated the author of the text to accept the premise.
 
To EVALUATE the argument involves (a) stating whether the argument is valid or not; (b) if it is valid, stating the name of the logical form that it exemplifies; (c) stating whether in the extractor's opinion the argument is sound; and (d) if the argument is not sound (or if it has a controversial premise) pointing out the weakest premise.
 
There are many mistakes that students frequently make when first trying to do extractos. Among the most common are the following:
 
1. Failing to locate the correct conclusion.
 
2. Failing to deflate. The lines must be restated in simple, literal terminology.
 
3. Insertion of sleeping partners (extra lines that play no role in the derivation of the conclusion).
 
4. Failure to put in valid forms. Extractors simply have to learn MP, MT, MMP, etc.
 
5. Failure to explain line by line.
 
6. Failure to evaluate properly. In many cases, I insist that you pick some line to criticize. Often, one of the premises is pretty clearly false. Points are taken off if the extractor simply claims in such a case that the argument is sound.
 
 
 
Do your best to Extract, Explain, and Evaluate an argument against LIB from this selection of text:
 
"According to Hobbism, if we know, of some man, what his beliefs and desires happen to be and how strong they are, if we know what he feels certain of, what he desires more than anything else, and if we know the state of his body and what stimuli he is being subjected to, then we may deduce, logically, just what it is that he will do-or, more accurately, just what it is that he will try, set out, or undertake to do. But this is inconsistent with Libertarianism. Libertarianism implies that, in one very strict sense of the terms, there can be no science of man. If we think of science as a matter of finding out what laws happen to hold, and if the statement of a law tells us what kinds of events are caused by what other kinds of events, then there will be human actions which we cannot explain by subsuming them under any laws. We cannot say, 'It is causally necessary that, given such and such desires and beliefs, and being subject to such and such stimuli the agent will do so and so'. For at times the agent, if he chooses, may rise above his desires and do something else instead." (Chisholm with slight editorial changes, "Human Freedom and the Self" 28)