72. Reason, Causes, and the Perfection of Reasoning

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Lecture Notes

Main Topics #

The Nature of Reason #

Reason as a thought (not merely a statement):

• Berquist defines reason primarily as a thought of why someone thinks a statement is true or false
• A reason may take the form of a statement, but the thought comes first; statements are derivative
• Distinction: A statement is true or false; a thought is the cognitive act that grounds belief

The two senses of “reason” in why-questions:

• The reason why I think something is true (subjective ground of my belief)
• The reason why something is true (objective cause or ground)
• These can diverge: I might think something is true for a weak reason, even if it is true for a different, stronger reason

Degrees of Reasons: From Weak to Perfect #

Weak reasons:

• Authority: Trusting Euclid or other respected figures; Aquinas says this is the weakest form in philosophy
• Example: Past experience (had a good meal at Restaurant A, bad meal at Restaurant B) suggests going to A
• Both are genuine reasons for thinking something but do not reveal why it must be so

Strong reasons:

• Measurement in geometry shows angles are equal in particular cases
• Better, but still not the best

Perfect reasons:

• Reveal the cause of why something must be so
• The straightness of intersecting lines is the cause of vertical angles being equal
• When you grasp the cause, your reason for thinking it is true is the reason why it is true
• This represents the “perfection” of reasoning

The Geometric Example: Vertical Angles #

The argument:

• When two straight lines intersect, vertical angles are equal
• Weak reason: They look equal
• Better reason: Measurement shows they are equal
• Perfect reason: The lines are straight; therefore angles on a line sum to two right angles; therefore opposite angles must be equal (by the axiom that equals subtracted from equals are equal)
• The straightness of the lines is the cause of the equality of the angles

The Distinction Between Weak Reasoning and Good Reasoning #

Restaurant example:

• My experience at A was good; at B was bad
• This is a reasonable guess but not a necessary reason
• I cannot give you a reason why you must get a better meal at A
• The cook may have changed, raw materials may differ, contamination may have occurred
• My reason for thinking I’ll have a better meal at A is not the cause of actually having a better meal

The complaining customer story:

• A man complains about everything: his meal, the bathroom sink being unusually low
• The sink’s position resulted from construction work that lowered the floor without adjusting pipes
• His wife must be “long-suffering”; the waitress must be patient
• Illustration: The man’s complaints reveal disconnection between his subjective impressions and actual causes

The Perfection of Reason in Understanding #

Why this matters:

• When my reason for thinking something is true is also the reason why it is true, I have genuine knowledge
• This is contrasted with mere opinion, authority, or example
• The geometer who understands the cause (straightness of lines) has better knowledge than one who only measures
• Understanding causes is what distinguishes wisdom from mere accumulated experience

Key Arguments #

Argument: Reasons as Thoughts vs. Statements #

1. A reason is fundamentally a thought of why someone thinks a statement is true or false
2. This thought may be expressed as a statement, but the statement is not the essential nature of the reason
3. A statement is true or false; a thought is a mental act
4. Therefore, defining reason primarily through statements risks confusing the derivative form with the fundamental nature

Argument: Authority as the Weakest Reason #

1. I may believe the Pythagorean theorem is true because Euclid says so
2. This gives me a reason for thinking it is true
3. But it does not give me the reason why it is true
4. My reason (appeal to authority) is weaker than the mathematical cause
5. Therefore, authority is the weakest form of reasoning

Argument: Example as Weak but Reasonable #

1. Experience at Restaurant A was good; at B was bad
2. This gives me a reason to prefer A
3. But it does not reveal the cause of better food at A (the cook, raw materials, contamination, etc. are all unknown)
4. Therefore, reasoning by example is reasonable but weak
5. Nevertheless, it may be “the best I can have in this case”

Important Definitions #

Reason (λόγος / ratio in Latin):

• A thought of why; the fundamental sense
• May be expressed as a statement or a sentence signifying the true or the false
• Involves grasping the cause or ground of why something is true

Perfect Reason:

• One in which the reason for thinking something is true coincides with the reason why it is true
• Reveals the cause (αἴτιον) of why something must be so
• Exemplified in mathematics when one understands the necessary cause

Weak Reason:

• One that gives ground for opinion but does not reveal the cause
• Does not explain why it must be so, only why I think so
• Includes authority, example, measurement in particular cases

Examples & Illustrations #

Geometric: Vertical Angles #

• Question: Are these angles equal?
• Weak answer: They look equal
• Better answer: I measured them and they are equal
• Perfect answer: The lines are straight; by the definition of a straight line, angles on a line sum to two right angles; therefore if a + x = 2R and b + x = 2R, then a = b (by subtracting equals from equals)
• The cause: The straightness of the lines

Practical: Restaurant Choice #

• The experience: Good meal at A one month ago; bad meal at B two weeks ago
• The reason for choosing A: My past experience
• Why it’s weak: The cook may have changed, ingredients may differ, I may have received a defective piece of meat
• The lesson: Experience gives a reasonable guess, not a necessary reason

Anecdotal: The Bathroom Sink #

• A restaurant had lowered the floor during construction but left the sink at its original height
• The sink now appears unusually high
• The complaining customer emerges from the bathroom and complains about it
• His wife “must be a long-suffering woman”
• The point: His imagination exaggerates the complaint; the cause (construction work) explains the unusual height

The Complaining Customer (Extended) #

• A man in a restaurant complains continuously to his waitress about his steak
• He warns the waitress: “If it isn’t done exactly this way, I will send it back”
• The waitress must prepare to deal with his complaints
• He goes to the bathroom, returns, and complains about the sink: “It was like this” (gesturing at the unusual height)
• His wife appears not to believe his exaggeration
• The humor: The man’s complaints about everything, even things beyond the restaurant’s control, reveal a habitual pattern of unreasonable judgment

Notable Quotes #

“The reason why someone thinks the statement is true or false may not be the reason why it is true.” — Berquist, illustrating the gap between subjective grounds and objective causes

“For someone whose reason for thinking these are true is that he measured them and they were [equal], and that’s why he thinks it’s always true—that’s not really such a good reason, is it? But me, who knows that their straightness makes them have to be equal—for me, the reason why I think they are equal is the reason why they are equal.” — Berquist, distinguishing weak from perfect reasoning

“The reason why it must be so… Not every reason is the reason why it must be so.” — Berquist, on the perfection of reasons

Questions Addressed #

What is the best reason you could give for saying angles are equal? #

Answer: Not that they look equal or that you measured them in this case. The best reason is that the lines are straight, which by necessity causes angles on a line to sum to two right angles, and therefore opposite angles must be equal. The straightness of the lines is the cause of the equality.

Is reasoning by authority a valid reason? #

Answer: Yes, it is a reason—but the weakest one. Aquinas says in philosophy, the argument from authority is weakest. You have a genuine reason for thinking something is true if an expert says so, but you do not have the reason why it is true. This applies to theology differently than philosophy.

Why is experience-based reasoning (Restaurant A vs. B) weak? #

Answer: Because it does not reveal the cause of why you would have a better meal at A. The cook could change, ingredients could vary, contamination could occur—any number of factors beyond what you experienced could change the outcome. You are making a reasonable guess, but guessing is not the same as having a reason that makes you think it must be so.

How should we think about reasons in practical decisions? #

Answer: Sometimes a weak reason is “the best thing I can have in this case.” You cannot give a necessary reason for choosing Restaurant A, but you can make a reasonable guess based on experience. This is different from geometry, where you can often grasp the perfect reason (the cause).

Pedagogical Emphasis #

Berquist uses this discussion to prepare students for understanding why the grasp of causes is essential to wisdom. In natural philosophy and metaphysics, grasping why something must be so—understanding the cause—is the goal. Weak reasons (authority, example, mere opinion) are how we often operate in practical life, but they should not be confused with genuine understanding.

The lecture also establishes a methodological principle: a well-formed reason should reveal the cause, not merely state a correlation or rely on external authority. This principle will be crucial for understanding Aristotle’s natural philosophy, where explaining why things move, change, and persist requires grasping causes.