This glossary defines the terms used across Poisonwell.com. Each definition includes a practical distinction so that labels clarify reasoning rather than end discussion.
Argument and Evidence#
| Term | Meaning | Diagnostic cue |
|---|---|---|
| Argument | Reasons offered in support of a conclusion. | What is the conclusion, and which premises support it? |
| Claim | A proposition presented as true or acceptable. | Can it be stated precisely enough to test? |
| Evidence | Information that raises or lowers support for a claim. | What difference should it make if true? |
| Relevance | A meaningful connection between a reason and the issue. | Does this information bear on the proposition or only change how we feel? |
| Burden of proof | Responsibility to supply adequate support for a claim. | Who asserted what, and what standard is appropriate? |
| Testimony | A person's report offered as a basis for belief. | Was the person in a position to know, and is there corroboration? |
Source and Credibility#
| Term | Meaning | Caution |
|---|---|---|
| Credibility | The degree of warranted trust in a source for a particular claim. | It is claim-specific, not a permanent moral score. |
| Expertise | Relevant knowledge or skill in a defined domain. | Match the field and task; prestige alone is not enough. |
| Position to know | Access or experience that makes knowledge of a fact possible. | Access does not guarantee accuracy. |
| Conflict of interest | A secondary interest that could improperly influence judgement or conduct. | Disclose and manage it; do not infer falsity automatically. |
| Corroboration | Independent evidence supporting the same proposition. | Sources copying one origin are not independent. |
| Provenance | The documented origin and custody of information or an object. | Origin can matter to authenticity without settling interpretation. |
| Primary source | Evidence created in the period or by a direct participant. | Primary does not mean unbiased, complete, or self-interpreting. |
Fallacies and Rhetorical Moves#
| Term | Plain-English definition | Different from poisoning the well |
|---|---|---|
| Poisoning the well | Preemptively disqualifying a participant or source so later contributions are not fairly considered. | The reference pattern. |
| Ad hominem | Using an irrelevant fact about a person against the person's argument. | Broader in timing and scope. |
| Appeal to motive | Treating a supposed motive as an answer to a claim. | Focuses on why the claim is advanced. |
| Guilt by association | Transferring discredit through a connection to another person or group. | The association supplies the discrediting reason. |
| Genetic fallacy | Judging a claim solely by its origin. | Can concern ideas and documents without a live participant. |
| Straw man | Replacing a position with a weaker or distorted version. | Changes the argument rather than the source's standing. |
| Red herring | Diverting attention to a side issue. | Need not involve a person or credibility. |
| Tu quoque | Answering criticism with a charge of hypocrisy. | Is normally a reply after criticism. |
| Loaded question | Embedding a disputed assumption in a question. | Constrains the answer through presupposition. |
| Fallacy fallacy | Assuming a conclusion is false because one argument for it is flawed. | A fallacy diagnosis does not settle truth. |
Constructive Practices#
| Term | Meaning |
|---|---|
| Principle of charity | Interpret an ambiguous contribution reasonably before criticising it. |
| Steelmanning | State a strong, recognisable version of the other position before responding. |
| Independent verification | Check a claim using evidence not controlled by the original source. |
| Proportionate confidence | Adjust trust by the quality and limits of evidence rather than choosing total trust or total distrust. |
Using Fallacy Labels Carefully#
A label should be followed by an explanation: quote the wording, name what it displaced, and say how the discussion can be repaired.
Calling criticism “ad hominem” or “poisoning the well” must not become a shield against questions about expertise, access, conflicts, or evidence.
References#
Bradley Dowden. Internet Encyclopedia of Philosophy. Internet Encyclopedia of Philosophy. Entries on Ad Hominem, Poisoning the Well, Straw Man, Red Herring, and related fallacies.
Peer-reviewed reference used for concise fallacy definitions and for the common classification of poisoning the well as preemptive circumstantial ad hominem.
Leo Groarke. The Stanford Encyclopedia of Philosophy. Metaphysics Research Lab, Stanford University. 2026. Sections on informal argument evaluation and ad hominem.
Scholarly overview used for the broader context of evaluating ordinary-language arguments and for the point that source criticism can sometimes be relevant rather than automatically fallacious.
Douglas N. Walton. Argumentation. Argumentation, volume 20, issue 3, pages 273–307. 2006. pp. 273–307.
Peer-reviewed analysis of poisoning the well as a strategic personal attack that can prevent an opponent from contributing arguments to a critical discussion.