more on this theme     |     more from this text

Single Idea 11071

[filed under theme 2. Reason / F. Fallacies / 1. Fallacy ]

Full Idea

The fallacy of 'affirming the consequent' is of the form φ→ψ, ψ, so φ.

Gist of Idea

'Affirming the consequent' fallacy: φ→ψ, ψ, so φ

Source

Robert Hanna (Rationality and Logic [2006], 5.4)

Book Ref

Hanna,Robert: 'Rationality and Logic' [MIT 2006], p.141

The 28 ideas from Robert Hanna

11046 Kantian principled rationality is recognition of a priori universal truths [Hanna]
11048 Humean Instrumental rationality is the capacity to seek contingent truths [Hanna]
11047 Hegelian holistic rationality is the capacity to seek coherence [Hanna]
11045 Most psychologists are now cognitivists [Hanna]
11053 Explanatory reduction is stronger than ontological reduction [Hanna]
11051 Frege's logical approach dominates the analytical tradition [Hanna]
11054 Scientism says most knowledge comes from the exact sciences [Hanna]
11055 Supervenience can add covariation, upward dependence, and nomological connection [Hanna]
11058 Logic is explanatorily and ontologically dependent on rational animals [Hanna]
11059 Circular arguments are formally valid, though informally inadmissible [Hanna]
11061 Intensional consequence is based on the content of the concepts [Hanna]
11063 Logicism struggles because there is no decent theory of analyticity [Hanna]
11067 Rational animals have a normative concept of necessity [Hanna]
11068 One tradition says talking is the essence of rationality; the other says the essence is logic [Hanna]
11071 'Affirming the consequent' fallacy: φ→ψ, ψ, so φ [Hanna]
11070 'Denying the antecedent' fallacy: φ→ψ, ¬φ, so ¬ψ [Hanna]
11072 Logic is personal and variable, but it has a universal core [Hanna]
11078 Intuition is only outside the 'space of reasons' if all reasons are inferential [Hanna]
11077 Intuition includes apriority, clarity, modality, authority, fallibility and no inferences [Hanna]
11080 Intuition is more like memory, imagination or understanding, than like perception [Hanna]
11081 Imagination grasps abstracta, generates images, and has its own correctness conditions [Hanna]
11083 A sentence is necessary if it is true in a set of worlds, and nonfalse in the other worlds [Hanna]
11082 Should we take the 'depictivist' or the 'descriptivist/propositionalist' view of mental imagery? [Hanna]
11084 Logical necessity is truth in all logically possible worlds, because of laws and concepts [Hanna]
11086 Metaphysical necessity can be 'weak' (same as logical) and 'strong' (based on essences) [Hanna]
11085 Nomological necessity is truth in all logically possible worlds with our laws [Hanna]
11089 Formally, composition and division fallacies occur in mereology [Hanna]
11088 We can list at least fourteen informal fallacies [Hanna]