Section 7, First Steps of Radical Translation: Simply to say that the underlying meaning varies, but the variance is not reflected in verbal disposiions may be making "a distinction without a difference." We can solve that via an abstract mapping of sentences among each other, or more concretely, via examination of radical translation (i.e., of a language that evolved completely autonomously, and without an interpreter). The only information available for such a translation are the stimuli of the native and the native's verbal and non-verbal behavior. Translation starts with events that are salient to both the native and the translator. The translator must query the native in a variety of stimulus conditions to determine the actual scope of a word, and to accomplish this must first learn how the native signals assent or dissent. The translator then needs to accumulate inductive evidence for both dissent and assent for each sentence, and discern causality properly.
Section 8, Stimulation and Stimulus Meaning: The native's assent is prompted by stimulations, not objects, and we should not think of them as a momentary static irradiation, but evolving patterns of a duration up to a temporal modulus, and in their spatial entirety. Further, such stimuli must be viewed not as particulars that are alike but as universals that repeat. The affirmative stimulus meaning is then the class of all such stimulations that prompt the native to assent, and the negative stimulus meaning those that would prompt his dissent; the stimulus meaning is the ordered pair of the two, but more completely, qualified with respect to the modulus, speaker, and time of assessment.
Section 9, Occasion Sentences. Intrusive Information: Occasion sentences are those that prompt assent or dissent only by current (relative to modulus) stimulation, whereas standing sentences would do so outside the modulus. Stimuli belonging to neither the affirmative nor negative stimulus meaning of an occasion sentence are caused by either "shock" or indecisiveness; for standing sentences it can also be due to irrelevance. Stimulus meaning is most important for occasion sentences. Sameness of stimulus meaning has shortcomings as defining the synonymy relation. Collateral information such as knowledge unique to the speaker, knowledge common only to the speaker's community, or hints provided linguistically to the speaker all create a mismatch. This is difficult to fix, in part because we cannot definitively separate what we are talking about from what we can say about it. Thus, sameness of stimulus meaning is too strict to expect between a native occasion sentence and its translation, so a translator must use significant approximation. Crucial in this project is the natural expectation that people will have simple expressions for common and salient events or objects.
Section 10, Observation Sentences: With expressions of color, the sameness of stimulus meaning comes very close to synonymy. In translation there is a shade grouping issue, but we can handle gradations using reaction time in addition to assent or dissent. In contrast, the stimulus meaning of an abstraction like "Bachelor" is not a good way to describe its meaning. We thus distinguish observation sentences, whose stimulus meaning does not vary with collateral information, and a continuum of observationality ranging from "Red" to "Bachelor." Highly observational expressions tend to have strong intersubjective correspondence of stimulus meaning. Observationality also varies with the modulus. Observation sentences are compatible with traditional notions, including "infallibility" and agreement among observers, though they are about ordinary things rather than sense data. Unlike stimulus meaning, observationality depends on similarity across speakers. Sentences learned ostensively tend to be highly observational. Those low in observationality tend to be based on a largely random personal history and have a random stimulus meaning.
Section 11, Intrasubjective Synonymy of Occasion Sentences: Stimulus meaning is a good stand-in for synonymy with respect to a particular speaker, including across languages, but it is not equivalent to "meaning." We can also test - but not easily hypothesize - intra-language synonymous sentences via the same speaker. Altogether, intrasubjective stimulus meaning is more useful than intersubjective, because it handles observation sentences, speaker shock, and to a significant extent, collateral information. However, in cases of words about words, or where collateral information is precisely the reason for the synonymy, or in the case of community information, even intrasubjectively it can fail. We should stick with short sentences, to avoid parsing errors, but can follow rules to construct longer sentences from them.