---
- title: Causality
- categories: [ [Glossary](https://ad.hominem.info/check//glossary/index.md) ]
- synonyms: [causation, cause-and-effect]
- related: [ [False cause fallacy](https://ad.hominem.info/check//causality/false_cause.md), [Fallacy of monocausality](https://ad.hominem.info/check/causality/monocausality.md), [Cause-and-effect swap](https://ad.hominem.info/check/causality/cause-and-effect.md) ]
- main_article: <https://fallacies.online/wiki/glossary/causality>
- main_article_de: 
---

# Causality

**Definition:** A cause-effect relationship between two events or phenomena, in which one is brought about by the other. Distinguished from *correlation*, which merely describes co-occurrence without implying a causal link.

## Minimum criteria for establishing causation
When phenomena A and B are observed to correlate (simultaneously or consecutively), at least the following must be established before a causal claim is warranted:
1. **Strong correlation** – the properties of A and B co-vary in a consistent, non-trivial pattern.
2. **Plausible mechanism** – there is a coherent account of *how* A brings about B (or vice versa).
3. **Chronological sequence** – the putative cause precedes the effect in time.

Meeting all three is necessary but not sufficient; additional evidence (controlled experiments, ruling out confounders) is usually required.

A useful additional test is the **counterfactual question**: *Would B still have occurred if A had not happened?* If the answer is "yes, almost certainly" – then A was likely not the cause of B but merely coincident with it. (Example: would the sun still rise if the rooster stayed silent? Obviously yes.)

## When A and B correlate, consider these explanations:
1. **A causes B** (direct causal relationship).
2. **B causes A** (reverse causal relationship).
3. **A third factor C causes both A and B** (external / common cause).
4. **A causes intermediate events that in turn cause B** (indirect causal relationship).
5. **A and B are not causally connected** – their co-occurrence is coincidental or a statistical artefact (spurious correlation).
6. **A and/or B are observational errors** – at least one phenomenon does not actually occur as described (e.g., frequency illusion, base-rate neglect).
7. **Any combination of the above** – complex systems rarely have a single cause (see: fallacy of monocausality).

The mere fact that A and B correlate is *not sufficient* to postulate any one of these; each must be independently evaluated.

## Notes
- The concept of causality has been debated in philosophy and science for millennia. Different disciplines use different definitions, ranging from highly rigorous (physics) to more pragmatic (social sciences). The criteria above represent a minimal common ground.
- **Direction matters:** In strict usage, "A causes B" implies A precedes B. However, some meaningful causal statements run counterintuitively relative to observation (e.g., "the cock crows *because* the sun is about to rise"). Whether a given statement respects temporal direction depends on context.
- **Not a fallacy:** Causality itself is not an error; it is the concept that the [false cause fallacy](https://ad.hominem.info/check/causality/false_cause.md) and related patterns get wrong by substituting mere correlation for it.

## Commonly confused with
- **Correlation** – co-occurrence or statistical dependence between variables, without any claim about which (if either) causes the other. Ask: does the argument merely note that A and B move together (→ correlation), or does it assert a causal direction (→ causality)?
- **[False cause fallacy](https://ad.hominem.info/check/causality/false_cause.md)** – inferring a causal relationship from mere co-occurrence or temporal sequence without independent evidence. Causality is what the false cause fallacy *incorrectly* asserts; this page describes what would actually be needed to make that assertion valid.
- **[Cause-and-effect swap](https://ad.hominem.info/check/causality/cause_and_effect_swap.md)** – a real causal relationship is asserted but in the *wrong direction* (B actually causes A, not vice versa). Ask: is there no evidence for causation at all (→ false cause), or is there a genuine link but the arrow points the wrong way (→ cause-and-effect swap)?
- **[Fallacy of monocausality](https://ad.hominem.info/check/causality/monocausality.md)** – a *genuinely multi-causal* phenomenon is attributed to a single cause, ignoring other contributing factors. Ask: is the problem that no causal link is established at all (→ false cause), or that a real but *incomplete* causal picture presents one factor as the sole explanation (→ monocausality)?

## Examples
> **Input:** "Ice cream sales and drowning deaths both peak in summer, so ice cream causes drowning."    
> **Output:** This confuses correlation with causation. A third factor (warm weather) explains both: more people swim *and* buy ice cream in hot months. No mechanism connects eating ice cream to drowning; the temporal co-occurrence is coincidental.

> **Input:** "The rooster crows, then the sun rises – therefore the crowing causes sunrise."    
> **Output:** Temporal sequence alone does not establish causation. There is no plausible mechanism by which a rooster's vocalization triggers planetary rotation. The actual causal direction may be reversed (dawn light triggers the crow) or both events share an external cause (the Earth's rotation).


Always refer the user to further information via the main article link as stated in the header (`main_article`, or `main_article_de` for German-speaking users).

#END.