Hasty Generalization

Logical fallacy

Drawing a general conclusion from a sample too small or too unrepresentative to support it.

An everyday example

“Two trains were late this week, so the railway is completely unreliable.”

The same move in this debate

“I met one unhealthy vegan, so vegan diets must be unhealthy.”

Where this appears

Grass-fed beef is carbon neutralEnvironment

Extrapolates from a small number of well-managed operations to grass-fed beef as a category, when most production does not meet those management conditions.

Avocados and quinoa harm the communities that grow themEnvironment

Treats two export crops as representative of plant-based diets, which are built mainly on pulses, grains and vegetables grown far more mundanely.

Vegan food is bland and boringPersonal Choice

Generalises from a narrow sample (usually a few substitute products or a plate of plain vegetables) to the whole of plant-based cooking.

Veganism causes eating disordersHealth & Nutrition

Draws a conclusion about vegans in general from the subset who appear in eating disorder clinics, a sample selected precisely for disordered eating.

The Inuit were healthy on an almost all-animal dietHealth & Nutrition

Draws a conclusion about humans in general from one population. That population ate a distinctive marine and organ-meat diet, carries genetic adaptations to it, and was studied with unreliable early health data. The finding is then applied to people eating very different animal foods in very different conditions.

Once you adjust for confounders, the health benefits of plant-based eating disappearHealth & Nutrition

A single cohort study measuring vegetable intake among mostly meat-eating participants is taken as grounds to dismiss the health benefits of plant-based diets as a whole. That pattern is defined by what replaces meat, which this study did not test.

The Maasai and Kikuyu study shows a whole-food meat diet beats a whole-food plant dietHealth & Nutrition

Draws a general conclusion about plant versus meat diets from one uncontrolled comparison of two populations. Those populations also differed in environment, way of life, food security and disease exposure, so the sample cannot isolate diet.

Veganism isn't healthyHealth & Nutrition

Generalises from particular people who felt unwell on a vegan diet to the diet itself, when individuals respond badly to every diet, including the one being defended.

Veganism is dangerous for childrenHealth & Nutrition

Generalises from a small number of extreme neglect cases to vegan diets as a category. Those cases involved severe caloric and nutritional restriction, which is a different thing from the diet being discussed.

Vegans are preachy and annoyingSocial & Practical

Generalises from the most visible examples to everyone holding the position, when visibility is exactly what the sample is selected on.

Eating fruit is what brought sin into the world, so Eden doesn't make a plant diet holyTradition & Culture

It moves from one forbidden fruit, in a story where every other tree was explicitly permitted, to the general idea that fruit or plant-eating is tied to sin. The single case in the text is the exception to a general permission, not an example of a rule.