50. Fallacies, Deception, and the Two Sources of Error

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Lecture Notes

Main Topics #

The Nature of Fallacies and Their Two Categories #

Fallacy (Locus Sophisticus): A fallacy is that which causes failing or deceiving (decisio). Something appears to be what it is not, giving apparent firmness to sophistical arguments. Deception requires ignorance in the deceived person—the fallacy itself does not deceive unless ignorance is present.

Two Fundamental Divisions:

• Fallacies from speech (ex parte vocis): Arise when the unity of a voice creates belief in the unity of the thing signified by that voice. Examples include equivocation and amphiboly.
• Fallacies from things (ex parte rei): Arise when things that come together in some way appear to be one simply, when they are not. The cause of deception is in the things themselves, though speech is used as a tool to express it.

This distinction follows Alexander of Aphrodisias, Albert the Great, and Thomas Aquinas.

The Root of Error: Two Sources #

Error originates from two distinct sources:

1. Defect of understanding: When the mind lacks foundation in truth or the power to judge truth. Such a person “easily picks up” error when facing difficult questions (like one who easily catches a cold).
2. Vice of will (appetite): When one acquires moral vice through repeated bad acts, the heart becomes “hard” and reason is blinded. This is not a defect of power but a corruption of the will’s orientation.

These two sources can operate independently or together.

Shakespeare’s Illustration: Fog and Filth #

The witches’ couplet in Macbeth encodes the two sources of error:

• “Fair is foul and foul is fair”: The confusion possible between good and bad
• “Hover through the fog and filthy air”: The two causes of this confusion
  • Fog = confusion of mind, defect of reason, ignorance that obscures clear judgment
  • Filth = viciousness of heart, moral vice that blinds reason

Shakespeare uses trochaic meter (unusual, reversed iambic meter) to indicate something not ordinary, reinforcing the unnaturalness of the witches and their message. The heavy alliteration in f-sounds (fair, foul, fog, filthy) emphasizes the two errors and their causes.

Shakespeare demonstrates this in other passages:

• Twelfth Night: “There is no darkness but ignorance”—ignorance as fog
• The Tempest: “The ignorant fumes that mantle their clear reason”—fog explicitly obscuring reason
• Antony and Cleopatra: “When we in our viciousness grow hard… in our filth drop our clear judgments, make us adore our errors”—filth of heart corrupting judgment
• King Lear: “Wisdom and goodness to the vile seem vile; filth savor but themselves”—vice inverts the perception of values

The Role of Distinction and Likeness in Preventing Deception #

The fundamental problem in all fallacy: In every fallacy, both from diction and from things, deception arises from inability to discern the same from the other (idem a diverso).

Likeness as a cause of deception: Likeness is a great cause of deception. If you do not see the differences among similar things, you can be deceived. This is why the second and third tools of dialectic (distinguishing word senses and finding differences of things) precede the fourth tool (considering likeness).

Example: The eight senses of the word “in” are very similar to each other, making it easy to be deceived by equivocation unless one carefully distinguishes them.

Reason requires distinction and order: Reason is defined as the ability to “look before and after,” but one cannot look before and after (perceive order) unless one can first perceive distinctions. Order presupposes distinction—you must know things are distinct (one is not the other) before you can know they are in order (one is before or after the other).

Key Arguments #

On Distinguishing Fallacies from Speech and Things #

From Thomas Aquinas (De Fallacies, Chapter 4):

• From the unity of voice comes belief in unity of thing signified
• From the coming together of things comes apparent unity when things are truly multiple
• Albert the Great adds: “The beginning of deception is in speech and the fallacies in diction. And the fallacies outside of diction is taken from the thing originally.”

On Error from Defect of Understanding #

From Thomas (via Boethius analogy):

• The intellect is to reason as the center is to the circle
• Reason discurrit (runs around), considering acts and defects in relations
• Unless reason resolves to an understanding of the true, reason is vain and does not reach its goal
• Some people “always learning and never coming to a knowledge of the truth” (2 Timothy 3:7)
• The doubt comes about “ex parte rei” (from the side of the thing itself)

On Error from Vice of Will #

Process:

1. Through repeated bad acts, one acquires the habit of moral vice
2. Habit becomes “hard” (difficult to change)
3. This hardness of heart leads to misery (for error is a great part of misery)
4. The vicious person’s reason becomes blinded by the filth of their heart
5. They come to “adore their errors” and proceed to confusion (opposite of glory)

Important Definitions #

Fallacy (Locus Sophisticus / Decisio): The cause of failing or deceiving; distinguished from dialectical places by being sources of apparent (not genuine) firmness in argument.

Deception (Deceptio): Requires both a fallacy and ignorance in the deceived person. A fallacy can exist without deceiving anyone if that person lacks ignorance.

Fog (Metaphorical): Ignorant fumes; defects in the knowing powers that obscure clear reason and truth.

Filth (Metaphorical): Viciousness; corruption in the desiring powers (appetites) that blinds reason to truth.

Idem a diverso: The inability to discern the same from the other; the fundamental problem underlying all deception.

Examples & Illustrations #

From Macbeth #

• Opening: Witches speak of “fair is foul and foul is fair”
• Act 1, Scene 1: The couplet expresses the two possible errors about good and bad, with their causes
• Before meeting the witches: Macbeth says “So foul and fair a day I have not seen”
• After the witches’ prophecies: Banquo remarks “Why do you start and seem to fear things that sound so fair?”

From Shakespeare’s Other Plays #

• Twelfth Night: Malvolio locked in darkness, told “there is no darkness but ignorance”
• The Tempest: Prospero’s charm on Alonso, Sebastian, and Antonio; their “ignorant fumes that mantle their clear reason” lifting as morning comes
• Antony and Cleopatra: Mark Antony describing how viciousness hardens the heart and filth drops clear judgments
• King Lear: Albany’s remark that to the vile, wisdom and goodness seem vile; filth savors only itself

The Word “In” #

The eight senses of “in” (being in a place, part in whole, genus in species, quality in substance, and others involving potentiality) are similar enough to cause confusion unless carefully distinguished.

Contemporary Application: Abortion Debate #

• Fog: Pro-abortion language obscures reality through terms like “pro-choice,” “termination of pregnancy,” “interfering with rights”
• Filth: Capital vices of lust (sexual irresponsibility) and avarice (abortion industry profit; avoiding financial burden of children) corrupt judgment
• The fog is so thick it requires “the knife of reason” to cut through it
• Multiple vices (pride, lust, avarice) work together to obscure the reality of what abortion is

Notable Quotes #

“Fair is foul and foul is fair, hover through the fog and filthy air.” — Macbeth, Act 1, Scene 1

“The ignorant fumes that mantle their clear reason.” — The Tempest (quoted by Berquist)

“When we in our viciousness grow hard… in our filth drop our clear judgments, make us adore our errors.” — Antony and Cleopatra (quoted by Berquist)

“Wisdom and goodness to the vile seem vile; filth savor but themselves.” — King Lear (quoted by Berquist)

“Error is a great part of misery.” — Thomas Aquinas, Summa Contra Gentiles

“The beginning of deception is in speech and the fallacies in diction. And the fallacies outside of diction is taken from the thing originally.” — Albert the Great

“In every fallacy, both in diction as well as outside of diction, there is generally deception from this: that one cannot discern the same thing and what is the same and what is other.” — Thomas Aquinas

Questions Addressed #

How do fallacies from speech differ from fallacies from things? #

Fallacies from speech arise from the multiplicity of meanings in words or expressions themselves. Fallacies from things arise because things that come together in some way appear unified when they are not. Both ultimately involve failure to distinguish the same (idem) from the other (diversum).

Why are fog and filth the two sources of error? #

Fog represents defect of understanding—ignorance and confusion that obscure truth. Filth represents vice of will—moral corruption that blinds reason. These correspond to the two fundamental powers of the human soul that can fail: intellect and will.

How does resemblance cause deception? #

When things are very similar, the mind can mistake one for another or fail to notice crucial differences. This is why distinguishing the senses of words and finding differences between things are essential tools against deception. Likeness is a “great cause of deception.”

What is the relationship between reason and the ability to perceive order? #

Reason is the ability to “look before and after”—to perceive order. But one cannot perceive order (before and after) without first perceiving distinction (that things are not identical). Therefore, order presupposes distinction as a foundation.