Section 1 of Chapter 4 is as follows:
(Most of the formatting is lost here.)

　　Our desire to deduce definite and categorical predictions stems from our desire to find out about the language faculty by adopting the methodological naturalist approach (summarized as the "Guess-Compute-Compare" (or "Guess-Deduce-Compare" method)) to the study of the language faculty and our belief that it is indeed possible to do so. The methodological proposal and its empirical illustration in this work is an attempt to substantiate this belief.
　　Feynman (1965/94: 152-153) remarks, "Another thing I must point out is that you cannot prove a vague theory wrong. If the guess that you make is poorly expressed and rather vague, and the method that you use for figuring out the consequences is a little vague―you are not sure, and you say, 'I think everything's right because it's all due to so and so, and such and such do this and that more or less, and I can sort of explain how this works ...', then you see that this theory is good, because it cannot be proved wrong! Also if the process of computing the consequences is indefinite, then with a little skill any experimental results can be made to look like the expected consequences." As we discussed in Chapters 2 and 3, the key to deducing definite and categorical predictions about the informant judgment is the recognition of the fundamental asymmetry in [P], repeated here.

[P]　　The fundamental schematic asymmetry
　a.　　The *Schema-based prediction:
　　　Every example sentence instantiating a *Schema is unacceptable with the specified interpretation pertaining to two expressions.
　b.　　　The okSchema-based prediction:
　　　　Some example sentences instantiating an okSchema are acceptable at least to some extent with the specified interpretation pertaining to two expressions.

Without its recognition, it would not be possible to deduce definite and categorical predictions about the informant judgment and expect them to be supported experimentally.
　　Just as in the case of our desire to deduce definite and categorical predictions, our desire to obtain experimental results in accordance with our definite and categorical predictions also stems from our desire to find out about the language faculty by adopting the methodological naturalist approach. Our definite and categorical predictions are in the form of a predicted schematic asymmetry, consisting of a *Schema-based prediction and its corresponding okSchema-based prediction, as in [P], repeated above. We now turn to how we can expect to obtain a confirmed predicted schematic asymmetry, i.e., an experimental result in accordance with [P], about individual informants' judgments.^FN1
　　As noted, one of the two defining features of the present work is its commitment to the methodological naturalist approach to the language faculty.^FN2 The "Guess-Compute-Compare" method was introduced in reference to the following remarks by Feynman.

　　　　　In general, we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is―if it disagrees with the experiment, it is wrong. That's all there is to it. (Feynman 1965/94: 150)

Feynman continues the above passage as follows:

　　　　　It is true that one has to check a little to make sure that it is wrong, because whoever did the experiment may have reported incorrectly, or there may have been some feature in the experiment that was not noticed, some dirt or something; or the man who computed the consequences, even though it may have been the one who made the guesses, could have made some mistake in the analysis. These are obvious remarks, so when I say if it disagrees with experiment it is wrong, I mean after the experiment has been checked, the calculations have been checked, and the thing has been rubbed back and forth a few times to make sure that the consequences are logical consequences from the guess, and that in fact it disagrees with a very carefully checked experiment." (Feynman 1965/94: 150-151)

　　When a physicist tries to make sure that an experiment is done very carefully, one of the first things they check is whether their experimental device, i.e., the device to measure what they are measuring, is properly designed, built, and operated. When a language faculty scientist tries to make sure that an experiment is done very carefully, what do they check? The experimental device in language faculty science, as it is being pursued here (at the present development of the research program), does not involve any hardware equipment, except computers for collecting informant judgments on-line and for some basic analysis of the results. But an experiment involves (i) example sentences, (ii) instructions to the informants including the intended interpretation in question, and (iii) the informants. The checking of how carefully the experiment has been conducted in language faculty science must therefore involve the testing of how effective our instructions are for a given informant and how clearly each informant understands the instructions as intended.
　　Recall that a predicted schematic asymmetry in language faculty science is given rise to by three types of hypotheses as in [H].

[H]　　Types of hypotheses:
　a.　　Universal hypotheses
　b.　　Language-particular hypotheses
　c.　　Bridging hypotheses

Given this, the issue raised by Poincaré and Duhem in relation to physical sciences, i.e., the under-determinacy-of-theory-by-data issue, applies to language faculty science clearly and straightforwardly, as discussed in Chapter 3: section 2. As also pointed out there, one way to cope with the issue is to focus on (a) particular hypothesis/ses among those that give rise to the predicted schematic asymmetry under discussion. We can do so effectively only by assuming the validity of the other hypotheses and by testing it in a Sub-Experiment, independently of the Main-Experiment in which the validity of the Main-Hypothesis/ses is tested.
　　As noted, an experiment in language faculty science involves (i) example sentences, (ii) instructions to the informants including the intended interpretation in question, and (iii) the informants. The example sentences are constructed in accordance with a *Schema and its corresponding okSchema, and the *Schema and the okSchema are constructed based on the hypotheses that give rise to the predicted schematic asymmetry in question, as discussed in Chapter 2: sections 3 and 4.
　　The Main-Experiment is designed under the assumption that the Sub-Hypotheses are valid. In order for the result of the Main-Experiment to be significant, it must be the case that our informants clearly understand our instructions, including the intended interpretations. If the Sub-Hypotheses are shown to be invalid in a Sub-Experiment, the result of the Main-Experiment cannot be taken as significant with regard to the validity of the Main-Hypothesis/ses. Likewise, if it is shown in a Sub-Experiment that the instructions including the intended interpretation in question are not effective for particular informants, the result of the Main-Experiment cannot be taken significant for those informants. It is in this sense that a Sub-Experiment to test the validity of the Sub-Hypotheses and the effectiveness of the instructions for individual informants can be understood as being analogous to the physicist's checking the effectiveness of their experimental device. Sub-Experiments and informant classification based on their results are, therefore, our way to maximize the reliability of our Main-Experiment in language faculty science.

FN1: Recall that it is our commitment to the internalist approach that leads us to make definite and categorical predictions about an individual informant's judgments.

FN2: The other is its commitment to the internalist approach. We are concerned with whether an individual informant's judgments are indeed in accordance with our definite and categorical predictions. We are not concerned with the "average" of a group of informants although we can address the average insofar as it is revealing about the judgments of individual informants. Illustration will be provided in Chapters 6 and 7.