Monday, November 19, 2012

Niemitz: "The evolution of the upright posture and gait—a review and a new synthesis" (2010)

The German biologist Carsten Niemitz has argued for a number of years that early hominids evolved their ability to walk on two legs not in order to walk on land, but to wade in shallow water. This paper reiterates this claim and collects a number of interesting observations in favor of it.

Nietmitz himself calls his hypothesis the "Amphibische Generalistentheorie" (p. 250). He explicitly contrasts it with Elaine Morgan's "Aquatic Ape Hypothesis" (pp. 249-50) which, admittedly, sometimes has been a little vague on whether it hypothesized a swimming ancestor of Homo Sapiens, or a wading one (i.e., a metaphorical dolphin, or a metaphorical hippopotamus?).

There are especially two aspects of his paper that I found quite striking. The first is his very nice collection of observations of wading among apes. (For further illustration, see also the footage on  YouTube of bonobos walking on two legs in water.) The other is the interesting observation that human beings seem to be insulated in a quite different way from apes, with much less body heat escaping through the fat on the thighs.

Friday, November 9, 2012

Stalnaker: "Presuppositions" (1973)

According to Robert Stalnaker, a person presupposes something
... just in case he is disposed to act, in his linguistic behavior, as if he takes the truth of P for granted, and as if he assumes that his audience recognizes that he is doing so. (p. 448; emphasis in original)
So for instance, Robert Stalnaker presupposes that all speakers are male. His linguistic behavior — here, writing this paper — reveals as much.

This pattern of thought is not just a matter of a pronoun here and there, as we can see if we look at the complete list of examples in the paper. I quote:
  1. In some cases, the central purpose of making a statement may be to communicate a presupposition which is required by that statement. For example, someone asks of my daughter, 'how old is he?' I answer, 'she is ten months old'. Or, a says, of the new secretary, 'Jennifer is certainly an attractive woman', b replies, 'Yes, her husband thinks so too'. (p. 449)
  2. For example, you ask, 'Who do you think will win the next presidential election?' I answer, 'George McGovern'. Now as a matter of fact in this conversation, we both presuppose from the beginning that Richard Nixon will be one of the candidates [...] Although neither of us does in fact act in any way that indicates that we take it for granted that Nixon will be a candidate, we are each disposed to so act, should the occasion arise. (p. 449)
  3. So, for example, I might say, 'Harry doesn't even realize that Nixon is going to run again'. Or, if I wanted to argue to a conclusion that required the premiss that Nixon was a candidate, I would not feel obliged to make that premiss explicit. So for example, I might argue, 'McGovern is going to win, so Nixon will lose'. (p. 449)
  4. If I say 'Even George Lakoff might be the Democratic nominee for President this year', I assert exactly what I would assert if I dropped the 'even'. (p. 453)
  5. I should emphasize that I do not want to rest any part of my argument on intuitive judgments that statements like 'Even Gödel could prove that theorem', 'If Nixon were President we'd be in a hell of a mess', and 'All of Lyndon Johnson's sons are bastards' in fact have truth values. (pp. 453-54)
  6. This principle helps explain the oddity of sentences like "John's aardvark is sleeping, and John has an aardvark'. (p. 454)
  7. If I say 'he is a linguist', there must be a particular male (the referent of 'he') who is presupposed to exist, but there is no single male whose existence is required by every use of that sentence. (p. 454)
  8. Thus 'John has children and all of his children are asleep' does not require the presupposition that John has children, even though the second conjunct does require this presupposition. (p. 455)
So, it would appear that men are fathers, scientists, and politicians, while women are daughters and secretaries. Only in "odd" sentences are the men placed in less paradigmatic scenes such as owning an aarvaark.

Thursday, November 8, 2012

Shuy: The Language of Defamation Cases (2010)

Roger Shuy is a so-called "forensic linguist," meaning that he appears as an expert witness in court cases that centrally involve questions about language, such as libel suits. He's written a number of books reporting on cases he's been involved in, the most recent being The Language of Defamation Cases.

His discussions are interesting because they show how quickly our unreflected notion of "meaning" starts to come undone when it gets exposed to the extreme hair-splitting that libel suits unavoidably entail. "What a statement means" becomes less rather than more clear when you look at it up close.

Frank Celebrezze v. The Plain Dealer

In 1986, the (Republican) Cleveland newspaper The Plain Dealer ran a series of stories about the (Democratic) Ohio Supreme Court justice Frank Celebrezze. Shortly thereafter, Celebrezze lost the race for re-election for the Supreme Court.

Before the publication of the articles, Celebrezze had taken campaign donations from labour unions, and some of these labour unions had members who were convicted of involvement in organized crime. As a judge, he had also voted against the conviction of people accused of organized crime at least twice.

So, one might conjecture that he was corrupt, and the mafia had bought his vote — and this was exactly what the two journalists Gary Webb and Mary Anne Sharkey claimed in a series of Plain Dealer articles, published immediately before the Supreme Court election.

Or was it? A closer reading of the articles in question revealed that they did not directly state that Celebrezze was corrupt, but one might argue that they suggested as much. Celebrezze consequently sued The Plain Dealer, and both he and the paper hired linguists to back their case.

Shuy represented the paper, and a local English professor was made Frank Celebrezze's case. Both experts wrote a report, but the case was eventually settled outside the court for an undisclosed sum.

The Apple of Discord

A number of quotes were brought to bear on the case. Most of them were headlines like this one:
Chief Justice denies mob role in contributions (p. 101)
But also some excerpts from the articles themselves were used, including this one:
In 1982 Celebrezze cast a tie-breaking vote against convicting Liberatore of arson. State records show that five days later, a Celebrezze campaign fund was given $5,000 … (p. 103)
The question was: Do these two sentences together imply that Celebrezze received the campaign donation as a result of his vote, or does it not?

The Argument Pro

According to Celebrezze's expert, both snippets of text indirectly implied that Celebrezze was guilty. With respect to the headline, the argument was a pragmatic one about presupposition:
If the headline had read Chief Justice Says Accusations Concerning Mob Role are False then the presupposition would have been that someone had made such accusations, not that the mob role was a given fact. (p. 101–102)
In other words, the claim is that the verb deny is veridical, or factive, while accusations concerning is not.

In the case of the quote, the argument refers to discourse coherence relationships:
Juxtaposing the two claims (that the judge had cast a tie-breaking vote and received money five days later) creates the obvious innuendo that there is a cause and effect relationship between the vote cast and the money paid. (p. 103)
So a reader searching for a coherent link between the two sentences will stumble upon cause–effect as the first likely candidate. This can be compared to the following examples, adapted from Jennifer Spenader:
  • Bill is worried that John might try to gain access to his safe. He'll have to change the combination. (therefore)
  • Bill is worried that John might try to gain access to his safe. He knows the combination. (because)
  • Bill is worried that John might try to gain access to his safe. I like spinach. (??)
Although the general claim that people will automatically search for discourse relations is sound enough, it is worth remembering that the choice of discourse relation is notoriously difficult to consistently agree on.

Arguments Contra

Shuy's own argumentation focused on the impotence of linguistics with respect to what a reader will extract from a text, or what the motives of a writer are:
There is no way that a linguist can actually reach inside the mind of the writer to determine what that writer intended. (p. 107)
There is no way that linguistic analysis can prove such attributions of a person's intentions. (p. 109)
The plaintiff's expert's use of expressions such as "must have," "they are affected," and "readers would" attribute results or behaviors [to the reader] that linguistic analysis simply cannot provide. (p. 111)
This is a surprisingly self-defying argument to hear from a person who is himself a forensic linguist. If it were really the case that linguistics has nothing to say about how a text works or what it reveals about the author, what is it doing in the courtroom in the first place?

The argument is also strange given that Shuy in the same chapter explains that he once had a courtroom disagreement with another linguist who "actually agreed with my conclusions but claimed that the field of linguistics could lead neither of us to such findings" (p. 98). To my ears, this sounds surprisingly close to saying that there is "no way that linguistic analysis can prove such attributions of a person's intentions."

The Flexibility of Forensic Linguistics

Further, when Shuy appears on the other side of a court case, he also seems to embrace a much more liberal approach to meaning:
Otherwise benign words and expressions, such as "made plans," "was alone," "secretly left the house," "went unanswered," "left town," and "living with," can convey meanings far beyond their usual dictionary senses, especially in the context of a broadcast about a murder. (p. 61–62)
But oddly, this is not the case with words like deny in the context of newspaper reporting on mob crime.

It seems that the conclusion we can draw is that linguistics either can or cannot say something about meaning, depending on whom its employer is on a given day. In the murder case (chapter 4), journalists are thus clever manipulators setting up snares for their helpless sources and listeners:
Most listeners are not very likely to notice the discourse framing of the broadcasts or that there was little attempt to clarify important ambiguities. (p. 68)
But in the corruption case (chapter 7), they have regained their agency, and the newspaper is liable only for explicit accusations, not innuendo:
… there is no such accusation in the articles, which present the facts about the relationship between the plaintiff and the local unions … The Plain Dealer claimed that the readers could draw whatever conclusions, if any, that these facts suggest to them. (p. 115)
Probably, the oscillation between these two poles of semantic theory is destined to go on as long as linguists continue to see meaning as a feature of words rather than situations.

Wednesday, November 7, 2012

Vendler: "Each and Every, Any and All" (1962)

This paper was first published in Mind in 1962, by just like everybody else, I read the version reprinted in the Linguistics in Philosophy (1967). It discusses the meaning of the words in the title and is famous for having described the meaning of any in terms of a certain "freedom of choice" (p. 80).

Each, Every, and All

Vendler describes the differences between each, every, and all in terms of collective reference vs. individual reference. His theory is that all is collective, while each and every are distributive.

We thus have differences like
  • You can buy each of these items for $5 (distributive)
  • You can buy all of these items for $5 (collective)
Every, on the other hand, can be seen as a quantification over all the distributive attributions so that "every is between each and all" in meaning (p. 77). We thus get — according to my intuitions — slightly more ambiguous examples with every:
  • You can buy every one of these items for $5
According to my intuition, this could lean towards both a collective ($5 in total) and a distributive reading ($5 per item).

The Blank Check

Vendler describes his ideas about any nicely in this quote:
To say
Any doctor will tell you …
is to issue a blank warranty for conditional predictions: you fill in the names. You choose Dr. Jones; well, then he will tell you if you ask him. You pick twenty-five others; then, I say, they will tell you if you consult them. (p. 85)
 This means that
… the any-proposition is an unrestricted warranty for conditional statements or forecasts and, we may add, for contrary-to-fact conditionals. In other words, to draw an obvious conclusion, it is an open hypothetical, a lawlike assertion. (p. 89)
 I like the phrase "open hypothetical." It both highlights why any can be used in couterfactuals and other modals, and why it does not have existential import.

Vendler also notes that every single time any is used, it issues this blank warranty anew:
… I can certainly not say
*He took any one
even if you acted on my words: Take any one. […] Any calls for a choice, but after it has been made any loses its point. (p. 81)
In other words, once all the facts are settled, you cannot use any to make a report, since "facts are not free" (p. 84).

Any and The Pragmatics of Preferences

One more quote from his explanation:
With Take any one, it is up to you to do the determining; here it does not make sense to ask back, Which one? Thus while in the former case [Take one] I merely fail to determine, in the latter case [Take any one] I call upon you to determine, in other words, I grant you unrestricted liberty of individual choice. (p. 79–80)
He notes that this also explains why a command like You must take any seems odd. Interestingly, though, the British National Corpus does contain examples like the following:
  • You must report any losses immediately.
It is probably fair to paraphrase this sentence as
  • If you have any losses, you must report them immediately.
So it appears that you can in fact order people to take any apple, but only if they are placed in an environment in which they are exposed to apples, and they be tempted to not take all of them (so to speak).

A Probabilistic Interpretation of Any

The last thing Vendler does in the article is to informally sketch a way that the difference between any, every, and all could be implemented in a compositional probabilistic semantics:
A bag contains a hundred marbles. We inspect ten at random and all ten are red. Then the probability that any one marble we care to pick out of the hundred will be red is quite high. Yet the probability of every one's being red is much lower. (p. 94)
 I interpret this the following way: When you evaluate the formula
  • All the marbles are red.
you are really asking for the posterior probability that the relevant parameter is 1. When you ask
  • Some of the marbles are red.
you are asking for the posterior probability that the parameter is larger than 0. However, when you evaluate the formula
  • Any marble we draw will be red.
you are looking for the posterior probability that one randomly drawn marble will be red, given your evidence. This amounts to summing up the probabilities of the statements
  • The bag contains 100 red marbles, and if I draw one at random, it will be red.
  • The bag contains 99 red marbles, and if I draw one at random, it will be red.
  • The bag contains 98 red marbles, and if I draw one at random, it will be red.
To take an example with slightly lower numbers, suppose I have drawn a marble twice from a bag of 10 marbles, and that in both cases, I drew a red marble. Then the posterior probability of the different parameter settings are shown in the graph below:


With these numbers, we get the probabilities
  • P("All marbles are red") = P(p = 1 | k = 2, n = 2) = 26%
  • P("Some marble is red") = 1 – P(p = 0 | k = 2, n = 2) = 1 – 0% = 100%
  • P("Any marble is red") = Σi P(p = pi | k = 2) * P(k = 1 | p = pi, n = 1) = 79%
The sum in the last line then ranges over all the parameters values p = 0, 0.1, 0.2, 0.3, …, 0.9, 1. As stated by Vendler, the probability of the any-sentence is substantially higher than the probability of the all-sentence.

Monday, November 5, 2012

Foucault: Lectures at College de France, 1973–74 (Lecture 1–3)

The academic year 1973–74 gave a course on the history of psychiatry. His approach during the course both rested on and differed from his work on madness ten years earlier.

The course mainly focuses on a period spanning roughly from the Revolution to the middle of the 1800s. Foucault's hypothesis is that the function of the psychiatric reforms of that period was to implement the new techniques of control that he calls "disciplinary power."

The Asylum as a Battlefield

This means that he frames the idea behind the psychiatric system essentially as one of fighting and defeating the patient:
So what is organized in the asylum is actually a battlefield. (p. 7)
What is involved is the confrontation of two wills, that of the doctor and those who represent him on one hand, and then that of the patient. What is established, therefore, is a battle, a relationship of force. (p. 10)
This is not completely without basis in the texts of the period. Foucault quotes a number of texts by Philippe Pinel and others that talk explicitly about "subjugating and taming the lunatic" (p. 8) or describe the patients as "individuals who think they are superior to everyone else" (p. 4).

Being King in One's Head

One way to interpret this spite towards the insane is to see their madness as a refusal to accept as true what they are supposed to accept:
Whether you believe yourself to be a kind or believe that you are wretched, wanting to impose this certainty as a kind of tyranny on all those around you basically amounts to "believing one is a king"; it is this that makes all madness a king of belief rooted in the fact that one is kind of the world. Psychiatrists at the start of the nineteenth century could have said that to be mad was to seize power in one's head. (p. 28)
And while such a "madness of error" would be relatively harmless in a system of sovereign power, it is a provocative and potentially dangerous act in a system of disciplinary power, since it shows the bounds on that system's ability to "subjugate and tame." 

All Power is Physical

The term "power" is used here in the same partly idiosyncratic way as in other works by Foucault:
… in the asylum, as everywhere else, power is never something that someone possesses, any more than it is something that emanates from someone. Power does not belong to anyone or even to a group; there is only power because there is dispersion, relays, networks, reciprocal supports, differences of potential, discrepancies, etcetera. It is in this system of differences, which have to be analyzed, that power can start to function. (p. 4)
This leads to some interesting observations:
It seems to me rather that what is essential in all power is that ultimately its point of application is always the body. All power is physical, and there is a direct connection between the body and political power. (p. 14)
Disciplinary power, as a particular paradigm of control, is then one example of this:
… I think that in our society, disciplinary power is a quite specific modality of what could be called the synaptic contact bodies-power. (p. 40)
This specific "disciplinary technology" (p. 57) would then have a history that could be traced, just like, for instance, the use of contracts and the use of paper money have a specific history.


What is Disciplinary Power?

One of Foucault's big ideas is that this specific form of power was invented in a specific period and in specific places and then slowly made its way into more and more corners of society.

In these lectures, he reiterates the claim that these disciplinary techniques were invented in religious institutions such as monasteries (p. 41) and then applied to armies, prisons, schools, hospitals, and asylums.

As an example, he gives the new organization that the Gobelin school of tapestry started using in 1667, with age-dependent class divisions, supervised work, and regular written assessments (pp. 49–50).

Another example is the transformation of police work in the 18th century, with the introduction of the police report and a notion of curing the subject of the their bad behavior rather than simply punishing them. A whole machinery of writing and documenting ensued (p. 50).

With respect to armies, he also mentions that highly ceremonial practices or "war games" such as jousting were replaced by physical exercises such as marching in order to train the bodies of the soldiers. This had "hardly existed before," Foucault claims (p. 48).

The Consequences of Discipline

Under the old system of power, the power of sovereignty, "[t]he pinning of the subject-function to a definite body can only take place at time in a discontinuous, incidental fashion, in ceremonies, for example" (p. 44).

According to Foucault's hypothesis, this is changed radically under the new system, since one of the main functions of this system is cause people to internalize the norms of the system. Disciplinary power, by its very nature, thus
… looks towards the future, towards the moment when it will keep going by itself and only a virtual supervision will be required, when discipline, consequently, will have become habit. (p. 47)
Or, similarly:
One must be able to spot an action even before it has been performed, and disciplinary power must intervene somehow before the actual manifestation of the behavior, before the body, the action, or the discourse, at the level of what is potential, disposition, will, at the level of the soul. (p. 52)
A consequence of this set-up is that disciplinary power cannot simply be content with harassing or assaulting transgressions. Like the O'Brien character in 1984, it must attempt to cure it. This obviously entails the constant production of fringe bodies, and when new strategies are taken up, fringes of those fringes (p. 53).

Augustine: De Dialectica

Around the year 387, Saint Augustine wrote this little text on logic, spanning only about 20 pages. According to his own account in Retractationes, the book was never finished, and he lost his only copy of the manuscript. However, the text we have genuinely seems to be written by him.

In spite of its opening statement, "Dialectic is the science of disputing well" (p. 5/82), De Dialectica does not contain much that we would now recognize as logic. It's a discussion of a number of topics related to language, most notably ambiguity and etymology.


Truth Values and Dispute

One notable feature of Augustine's discussion of 'dialectics' is that he seems to take dispute to be more fundamental than truth values. A meaningful statement has a truth value in virtue of being up for discussion – not the other way around.

In his words:
For either a statement is made in such a way that it is held to be subject to truth or falsity, such as 'every man is walking' or 'every man is not walking' and others of this kind. Or a statement is made in such a way that, although it fully expresses what one has in mind, it cannot be affirmed or denied, as when we command, wish, curse, or the like. For whoever says 'go into the house' or 'oh that he would go into the house' [utinam pergat ad villam] or 'may the gods destroy that man' cannot be thought to lie or to tell the truth, since he did not affirm or deny anything. Such statements do not, therefore, come into question so as to require anyone to dispute them. (p. 6/85)
He consequently adopts the term "statements that require disputation" as a name for what we would call truth-functional statements (p. 6/85).

Eloquence and Proloquence

He later introduces the distinction "expressing" / "asserting" (eloquendo / proloquendo) to indicate the difference between the statements that "require questioning and disputing" and those that do not (p. 7/87).

This leads him, in the Chapter XII on "the force of words," to make he following wonderful comment on the relation between logic and rhetoric:
For although disputation need not be inelegant [ineptam] and eloquence need not be deceptive [mendacem], still in the former the passion of learning often – indeed, nearly always – scorns the pleasures of hearing, while the in the latter the more ignorant multitude [imperitior multitudo] think that which is said elegant is said truly. Therefore, when it becomes apparent what is proper to each, it is clear that a disputer who has any concern to make his points appealing will sprinkle them with rhetorical color, and an orator who wishes to convince people of the truth will be strengthened by the sinews and bones, as it were, of dialectic, which are indispensable to the strength of the body but are not allowed to become visible to the eye. (p. 13–14/103)
So logic and rhetoric are inner and outer values – but logic is not inner as in the soul, but inner as in internal organs.

An Observation on Implication

Another interesting feature is that he takes implication to be inherently connected to argumentation:
Whoever says 'if he is walking, he is moving' wishes to prove something, so that when I concede that this combined statement is true he only needs to assert that he is walking and the conclusion that he is moving follows and cannot be denied, or he need only assert that he is not moving and the conclusion that he is not walking must be agreed to. (p. 6/85)
It seems fair to say that Augustine thus sees the meaning of the implication as  given by its use in argumentation.

Signification and Writing

In Chapter V, Augustine gives a definition of a sign followed by a slightly strange qualification:
A sign is something which is itself sensed and which indicates to the mind something beyond the sign itself. To speak is to give a sign by means of an articulate utterance. By an articulate utterance I mean one which can be expressed in letters. [Signum is quod et se ipsum sensui et praeter se aliquid animo ostendit. Loqui est articulata voce signum dare. Articulatum autem dico quae comprehendi litteris potest.] (p. 7/87)
The intuition behind this comment seems to be the following: If something is said clearly and intelligibly, it can be broken up into its component parts (letters, or phonemes). However, this does seem on he face of it to make verbal understanding dependent on literary understanding.

But maybe this is only because we read too much into the word "letter":
For we misuse the term 'letter' when we call what we see written down a letter, for it is completely silent and is no part of an utterance but appears as the sign of an articulate utterance. In the same way [we misuse the term 'word'] when we call what we see written down a word, for it appears as the sign of a word, that is, not as a word but as the sign of a significant utterance. Therefore, as I said above, every word is a sound [omne verbum sonat]. (p. 7/89)
The theory thus seems to be this: The written word or letter is a sign because it evokes the spoken word or letter to the mind; and the spoken word or letter is a sign because it evokes its referent.

Ambiguity and Obscurity

In Chapter VIII, Augustine introduces a distinction between ambiguity and obscurity. This is not terribly important, but I find his explanation so nice that I wanted to quote it:
When little appears, obscurity is similar to ambiguity, as when someone who is walking on a road comes upon a junction with two, three, or even more forks of the road, but can see none of them on account of the thickness of a fog. Thus he is kept from proceeding by obscurity. […] When the sky clears enough for good visibility, the direction of all the roads is apparent, but which is to be taken is still in doubt, not because of any obscurity but solely because of ambiguity. (p. 14/105)
He goes on to complicate this distinction by distinguishing further between obscurity based on inaccessibility to the mind and to the senses, as in not recognizing a picture of and apple either because one has never seen an apple before, or because it is too dark (p. 14/105).

Problems with Category Membership

In his discussion of ambiguity, Augustine distinguishes between the vagueness of a word like man and more straightforward cases of homonomy. He calls these two phenomena univocal and equivocal meaning, respectively.

This would not in itself be particularly interesting if he didn't get himself into problems by suggesting that a univocal concept is characterized by having "a single definition" (p. 16/111). This of course raises some problems once we start looking for such a definition:
When we speak of a man we speak equally of a boy and of a young man and of an old man, equally of a fool and of a wise man [and a number of further examples]. Among all those expressions there is not one which does not accept the name 'man' in such a way as to be included by the definition of man. For the definition of 'man' is 'a rational, mortal animal' [animal rationale mortale]. Can anyone say that only a youth is rational, mortal animal and not also a boy or an old man, or that only a wise man is and not only a fool? (p. 16–17/111)
So in order to save his definition, Augustine has to assert that a fool is rational, something he seems to sense the problem with:
One may wonder how a boy who is small and stupid [parvo aut stulto], or at least silly [fatuo], or a man who is sleeping or drunk or in a rage, can be rational animals. This can certainly be defended, but it would take too long to do this because we must hasten on to other subjects. (p. 17/111)
This is approximately the same rhetorical strategy he used when defining a sign back in Ch. V:
Whether all these things that have been defined have been correctly defined and whether the words used in definition so far will have to be followed by other definitions, will be shown in the passage in which the discipline of defining is discussed. [This part was never written.] For the present, pay strict attention to the material at hand. (p. 7/87)

Criticism of the Stoic Theory of Etymology

In addition to being an interesting text in its own right, Augustine's tiny book is also one of our prime sources for the Stoic theory of where meaning comes from.

The upshot of this theory is apparently the following: Every word has a meaning which derived metonymically from another word, and ultimately, these chains of metonymies all point back towards an original sound iconicity. Thus, Augustine reports that in order to avoid infinite regress,
… they assert that you must search until you arrive at some similarity of the sound of the word to the thing, as when we say the 'the clang of bronze' [aeris tinnitum], 'the whinnying of horses' [equorum hinnitum], 'the bleating of sheep' [ovium balatum], 'the blare of trumpets' [tubarum clangorem], 'the rattle of chains' [stridorum catenarum]. For you clearly see that these words sound like the things themselves which are signified by these words. But since there are things which do not make sounds, in these touch is the basis for similarity. If the things touch the sense smoothly or roughly, the smoothness or roughness of letters in like manner touches the hearing and thus has produced the names for them. For example, 'lene' [smoothly] itself has a smooth sound. Likewise, who does not by the name itself judge 'asperitas' [roughness] to be rough? It is gentle to the ears when we say 'voluptas' (pleasure); it is harsh when we say 'crux' (cross). This the words are perceived in the way the things themselves affect is. Just as honey itself affects the taste pleasantly, so its name, 'mel,' affects the hearing smoothly. 'Acre' (bitter) is harsh in both ways. Just as the words 'lana' (wool) and 'verpres' (brambles) are heard, so the things themselves are felt. The Stoics believed that these cases where the impression made one the senses by the sounds are, as it were, the cradle of words. From this point they believed that the license for naming had proceeded to the similarity of things themselves to each other. (p. 10/95)
Augustine's main beef with this theory seems that it is too speculative:
Even though it is is a great help to explicate the origin of a word, it is useless to start on a task whose prosecution could go on indefinitely. For who is able to discover why anything is called what it is called? (p. 9/93)
As an example, he gives a couple of hypotheses about the origin of the word verbum, asking "But what difference does this make to us?" (p. 9/93).

Varieties of Metonymic Shifts

The avenues by which words can jump from meaning to meaning are quite diverse. Twice in the text, Augustine gives a list of relationships that can warrant metonymic slides, once in chapter on "the origin of words" (Ch. VI) and once in the chapter on "equivocation" (Ch. X).

Here's the list from Chapter VI, page 11/97:
Proximity [vicinitas] is a broad notion which can be divided into many aspects:
  1. from influence, as in the present instance in which an alliance [foedus] is caused by the filthiness of the pig [foeditate porci];
  2. from effects, as puteus [a well] is named, it is believed, from its effect, potatio [drinking];
  3. from that which contains, as urbs [city] is named from the orbis [circle] which was by ancient custom plowed around the area […];
  4. from that which is contained as it is affirmed that by changing a letter horreum [granary] is named after hordeum [barley];
  5. or by transference [abusionem], as when we say horreum, and yet it is wheat that is preserved here;
  6. or the whole from the part, as when we call a sword by the name 'mucro' [point], which is the terminating part of the sword;
  7. or the part from the whole as when capillus [hair] is named from capitis pilus [hair of the head].
Here's the list from Chapter X, page 19/117–119:
I call it transference [translatione]
  1. when by similarity [similitudine] one name is used of many things, as both the man, renowned for his great eloquence, and his statue can be called 'Tillius.'
  2. Or when the part is named from the whole, as when his corpus can be said to be Tillius;
  3. or the whole from the part, as when we call whole houses 'tecta' [roofs].
  4. Or the species from the genus, for 'verba' is used chiefly of all the wors by which we speak, although the words which we decline by mood and tense are named 'verba' in a special sense.
  5. Or the genus from the species as 'scholastici' [scholars] were originally and properly those who were still in school, though now all who pursue a literary career [litteris vivunt] use this name.
  6. Or the effect from the cause, as 'Cicero' is a book of Cicero's.
  7. Or the cause from the effect, as something is a terror [terror] which causes terror.
  8. Or what is contained from the container, as those who are in a house are called a household.
  9. Or vice versa, as a tree is called a 'chestnut.'
  10. Or if any other manner is discovered in which something is named by a transfer, as it were, from the same source.
You see, I believe, what makes for ambiguity in a word.
The itemization is not in the original. It is interesting that many of these examples are slightly strange or would be analyzed differently (but equally speculatively) today; the relationship of a chestnut tree and a chestnut would, e.g., probably be seen as producer–product relation rather than container–contained.

Word, Thing, Concept, and Word-Thing

One last thing that I want to mention is the rather complicated four-part distinction that Augustine introduces in chapter VI between verbum, dicibile, dicto, and res.

The last tree can roughly be glossed as concept, word, and thing:
Now that which the mind not the ears perceives from the word and which is held within the mind itself is called a dicibile. When a word is spoken not for its own sake but for the sake of signifying something else, it is called a dictio. The thing itself which is neither a word nor the conception of a word in the mind [verbi in mente conceptio], whether or not it has a word by which it can be signified, is called nothing but a res in the proper sense of the name. (p. 8/89)
The verbum, however, is a word considered as a thing one can refer to:
Words are signs of things whenever they refer to them, even though those [words] by which we dispute about [things] are [signs] of words. […] When, therefore, a word is uttered for its own sake, that is, so that something is being asked or argued about the word itself, clearly it is the thing which is the subject of disputation and inquiry; but the thing in this case is called a verbum. (p. 8/89)
We thus have here a kind of use/mention distinction, although put in a slightly different vocabulary.