Logic Reasoning Skills — Development skill for Claude Code

Logic & Reasoning Skills

Three skills for Claude that bring formal and informal logic into your workflow. Built by synthesizing four open-access logic textbooks into operational instructions Claude can follow.

Each skill is a self-contained `SKILL.md` file — no scripts, no dependencies, no external references. Claude reads the file and gains the relevant analytical capability.

The three skills

argument-analyst

Systematic six-phase analysis of any argumentative text.

**What it does:**

1. Argument detection — identifies which parts of a text are arguments (reasons given for a conclusion) vs. explanations, descriptions, or bare assertions.
2. Reconstruction in standard form — extracts premises and conclusions, numbers them, marks their logical relationships, and resolves enthymemes (arguments with an unstated premise) through a five-step procedure: detect the gap, identify the addressee, generate competing candidate premises rather than one, tag each supplied premise by provenance (TEXTUAL / CONVENTIONAL / ANALYST), and stop at the charity ceiling rather than repairing an argument into one the arguer never made. The is-ought gap is handled as one case of this procedure.
3. Validity and soundness assessment — applies the informal test of validity (can you imagine a scenario where the premises are true and the conclusion false?) for deductive arguments; assesses inductive strength for statistical generalizations, analogies, causal claims, and inferences to the best explanation.
4. Fallacy detection — scans for 24+ named fallacies organized in four families.
5. Explanation quality — evaluates inference-to-best-explanation arguments against seven explanatory virtues (explanatoriness, depth, power, falsifiability, modesty, simplicity, conservativeness).
6. Verdict — overall assessment on a six-point scale from Sound/Cogent to Fallacious, plus Incomplete as stated for arguments that cannot be judged without a premise the text n