When we see a “result”, we wrongly assume that a specific cause we’re thinking of must have caused it.
Definition:
The converse error fallacy happens when we take a true statement like “If A, then B” and wrongly conclude “If B, then A”. For example:
If David is in love (A), he sends a message every day (B). [Main statement]
He sends a message every day (B). [Observation]
Therefore he must be in love (A). [Incorrect inference = fallacy]
In logic, if A is a sufficient condition for B, B is not necessarily a necessary condition for A. This fallacy ignores that an outcome may have multiple causes, not just one specific cause. Therefore, reversing a conditional relationship can lead us to a mistaken judgement.
Typical structure of this fallacy:
- If A, then B. [Main statement]
- B has occurred. [Observation]
- Therefore A has also occurred [1]. [Incorrect inference = fallacy]
Examples from real life:
1. In politics and human rights:
a) If a regime is authoritarian (A), it violates human rights (B). [Main statement]
The United States violated human rights by prosecuting Edward Snowden for exposing mass violations of privacy (B). [Observation]
Therefore the United States is an authoritarian regime (A). [Incorrect inference = fallacy]
Here, it should be noted that this argument wrongly assumes only authoritarian regimes violate human rights. The legal pursuit of Snowden happened in one of the world’s largest democracies. The US government did not deny the reports of mass surveillance of citizens, but instead of reforming the system, it criminalised the whistle-blower and drove him into exile. This example shows that violations of freedom of information and individual rights can also occur in democracies and should not be attributed solely to authoritarianism.
The fact that a country calls itself a democracy does not prevent it, in practice, from infringing freedom of information and individual rights.
In this example, the converse error leads us to attribute human rights violations only to authoritarianism and to ignore their relationship with power and interests within the structure of Realpolitik, whether in the form of dictatorship or democracy. In Realpolitik, the scope of individual freedom is defined not by the boundary of others’ freedom but by the interests of the hard core of power (the establishment).
b) If a person is a refugee, they have the right to international protection.
This person receives international protection, therefore they must be a refugee.
Here, it should be noted that stateless people, victims of human trafficking, or children crossing borders alone may also qualify for international protection without being official refugees.
2. In education:
a) If a pupil has obtained a high rank, they must have performed well in the exam.
This pupil’s rank is high, therefore they must have performed excellently in the exam.
Here, it should be noted that things like quotas, special advantages, or marking mistakes can affect the result.
Such a fallacy can conceal inequalities and make meritocracy merely appear to be in place.
b) If a pupil is studious, they always participate in class discussions.
This pupil participates in discussions, therefore they must be studious.
Here, it should be noted that joining class discussions can have many reasons and doesn’t always mean someone is studious.
Some pupils speak actively because of verbal skills, an interest in debate, or even a desire for attention, without having actually spent much time studying.
By contrast, some pupils, despite hard work and extensive study, do not participate in class discussions because of shyness, social anxiety, or negative past experiences.
This fallacy can lead teachers to unfair evaluations of pupils’ performance. Such evaluations can marginalise some talented pupils. Pupils themselves may also misinterpret their own or their classmates’ standing, which can undermine the confidence or motivation of some.
3. In consumer advertising:
a) If a product is expensive, it may be high quality.
This product is high quality, therefore it must be expensive.
Here, it should be noted that many high-quality products are reasonably priced due to competition or local production.
b) If a cosmetic cream is effective, there will be a lot of advertising about it.
There is a lot of advertising about this cream, therefore it must be effective.
Here, it should be noted that the amount of advertising depends more on the brand’s marketing budget than the product’s real quality. Companies with greater resources can capture the public’s attention through extensive advertising even if their product is not significantly different from other cheaper and less advertised options.
This fallacy may lead consumers to decide not on the basis of scientific and experiential comparison but merely on the number of advertisements, and it may cause smaller brands with quality products but limited advertising to be overlooked.
4. In everyday life:
a) If someone is a Swedish citizen, they can live in Sweden.
This person lives in Sweden, therefore they are a Swedish citizen.
Here, it should be noted that visiting students, refugees, or foreign workers can legally live in Sweden without being citizens.
b) If Sara is upset, she may become quiet.
She has become quiet, therefore she must be upset.
Here, it should be noted that Sara’s quietness could come from many reasons, like tiredness, being busy, illness, or focusing on work.
This fallacy in close relationships can create misunderstanding and misjudgement and can fuel emotional conflict.
Why is this fallacy dangerous?
● It leads to hasty and unfair judgements.
● It oversimplifies causal relationships.
● It can be used in media and advertising to mislead the public.
● It lays the ground for discrimination and stereotyping.
How can we recognise and respond to it?
To detect this fallacy, ask:
– Has the argument wrongly moved from the “outcome” to the “cause”?
– Is there only one possible “cause” for this “outcome”?
– Is the logical relationship between A and B bidirectional or one-way?
A suitable response might be: “It is true that B has occurred, but this does not necessarily mean that A has occurred. Other reasons may also exist.”
Conclusion:
The converse error fallacy tricks us into thinking that if a result happens, the specific cause we’re thinking of must have happened too. Yet many phenomena are multi-causal, and the relationship between cause and effect is not always reversible. Recognising this fallacy protects us against unsound arguments, misleading advertising, and unfair judgements.
[1] In this text, we use the labels “Main statement”, “Observation”, and “Incorrect inference = fallacy” to make the reasoning steps clearer for a general audience. In formal logic, however, the structure is usually presented as: “If P then Q” (conditional premise), “Q” (affirming the consequent), “Therefore P” (invalid inference). We deliberately chose simpler wording to enable readers without a background in formal logic to follow the examples more easily, while the academic equivalents remain Conditional premise, Affirming the consequent, and Invalid conclusion.