argumentation_schemes/catalog/
analogy.rs

1//! Analogical schemes: analogy, classification, commitment.
2//!
3//! Ref: Walton, Reed & Macagno 2008, Chapter 9 + Appendix 1.
4
5use crate::catalog::ANALOGICAL_ID_OFFSET;
6use crate::critical::CriticalQuestion;
7use crate::scheme::*;
8use crate::types::*;
9
10/// Return all analogical schemes.
11pub fn all() -> Vec<SchemeSpec> {
12    vec![
13        argument_from_analogy(),
14        argument_from_verbal_classification(),
15        argument_from_commitment(),
16    ]
17}
18
19/// Argument from Analogy (Walton 2008 p.315).
20pub fn argument_from_analogy() -> SchemeSpec {
21    SchemeSpec {
22        id: SchemeId(ANALOGICAL_ID_OFFSET),
23        name: "Argument from Analogy".into(),
24        category: SchemeCategory::Analogical,
25        premises: vec![
26            PremiseSlot::new("similar_case", "The analogous case", SlotRole::Property),
27            PremiseSlot::new(
28                "current_case",
29                "The case being reasoned about",
30                SlotRole::Property,
31            ),
32            PremiseSlot::new(
33                "property",
34                "The property that holds in the analogous case",
35                SlotRole::Proposition,
36            ),
37        ],
38        conclusion: ConclusionTemplate::positive(
39            "?property also holds in ?current_case because it holds in ?similar_case",
40            "?property",
41        ),
42        critical_questions: vec![
43            CriticalQuestion::new(
44                1,
45                "Are ?similar_case and ?current_case truly similar in relevant respects?",
46                Challenge::DisanalogyClaim,
47            ),
48            CriticalQuestion::new(
49                2,
50                "Is ?property the kind of thing that transfers between analogous cases?",
51                Challenge::RuleValidity,
52            ),
53            CriticalQuestion::new(
54                3,
55                "Are there relevant differences between ?similar_case and ?current_case that block the analogy?",
56                Challenge::DisanalogyClaim,
57            ),
58        ],
59        metadata: SchemeMetadata {
60            citation: "Walton 2008 p.315".into(),
61            domain_tags: vec!["analogical".into()],
62            presumptive: true,
63            strength: SchemeStrength::Moderate,
64        },
65    }
66}
67
68/// Argument from Verbal Classification (Walton 2008 p.320).
69pub fn argument_from_verbal_classification() -> SchemeSpec {
70    SchemeSpec {
71        id: SchemeId(ANALOGICAL_ID_OFFSET + 1),
72        name: "Argument from Verbal Classification".into(),
73        category: SchemeCategory::Analogical,
74        premises: vec![
75            PremiseSlot::new("subject", "The entity being classified", SlotRole::Agent),
76            PremiseSlot::new(
77                "classification",
78                "The classification being applied",
79                SlotRole::Property,
80            ),
81        ],
82        conclusion: ConclusionTemplate::positive(
83            "?subject has the properties associated with ?classification",
84            "is_a_?classification_?subject",
85        ),
86        critical_questions: vec![
87            CriticalQuestion::new(
88                1,
89                "Does ?subject actually fit the definition of ?classification?",
90                Challenge::PremiseTruth("classification".into()),
91            ),
92            CriticalQuestion::new(
93                2,
94                "Is ?classification the right category for this context?",
95                Challenge::RuleValidity,
96            ),
97        ],
98        metadata: SchemeMetadata {
99            citation: "Walton 2008 p.320".into(),
100            domain_tags: vec!["analogical".into(), "definition".into()],
101            presumptive: true,
102            strength: SchemeStrength::Moderate,
103        },
104    }
105}
106
107/// Argument from Commitment (Walton 2008 p.322).
108pub fn argument_from_commitment() -> SchemeSpec {
109    SchemeSpec {
110        id: SchemeId(ANALOGICAL_ID_OFFSET + 2),
111        name: "Argument from Commitment".into(),
112        category: SchemeCategory::Analogical,
113        premises: vec![
114            PremiseSlot::new(
115                "agent",
116                "The person who made the commitment",
117                SlotRole::Agent,
118            ),
119            PremiseSlot::new(
120                "commitment",
121                "The commitment that was made",
122                SlotRole::Action,
123            ),
124            PremiseSlot::new(
125                "claim",
126                "The claim that follows from the commitment",
127                SlotRole::Proposition,
128            ),
129        ],
130        conclusion: ConclusionTemplate::positive(
131            "?agent should act consistently with ?commitment, therefore ?claim",
132            "?claim",
133        ),
134        critical_questions: vec![
135            CriticalQuestion::new(
136                1,
137                "Did ?agent actually make ?commitment?",
138                Challenge::PremiseTruth("commitment".into()),
139            ),
140            CriticalQuestion::new(
141                2,
142                "Does ?claim actually follow from ?commitment?",
143                Challenge::RuleValidity,
144            ),
145            CriticalQuestion::new(
146                3,
147                "Have circumstances changed such that ?commitment no longer applies?",
148                Challenge::AlternativeCause,
149            ),
150        ],
151        metadata: SchemeMetadata {
152            citation: "Walton 2008 p.322".into(),
153            domain_tags: vec!["analogical".into(), "social_contract".into()],
154            presumptive: true,
155            strength: SchemeStrength::Moderate,
156        },
157    }
158}
159
160#[cfg(test)]
161mod tests {
162    use super::*;
163
164    #[test]
165    fn all_returns_three_analogical_schemes() {
166        assert_eq!(all().len(), 3);
167    }
168
169    #[test]
170    fn analogical_ids_are_in_offset_range() {
171        for s in all() {
172            assert!(s.id.0 >= ANALOGICAL_ID_OFFSET);
173            assert!(s.id.0 < ANALOGICAL_ID_OFFSET + 100);
174        }
175    }
176}
argumentation_schemes/catalog/analogy.rs

argumentation_schemes/catalog/
analogy.rs
