Equivocation

Logical fallacy

Using a single word in two different senses within one argument, so that a conclusion appears to follow when it does not.

An everyday example

“Nothing is better than lifelong happiness. A cheese sandwich is better than nothing. So a cheese sandwich is better than lifelong happiness.”

The same move in this debate

“'Free-range' means the birds are free.”

Where this appears

All of civilisation is about chasing trivial pleasuresEthics & Morality

The original claim used 'trivial pleasure' to mean a benefit that is slight compared with the suffering it costs. The reply switches to 'trivial' in the sense of anything beyond survival, such as art, travel or comfort. It then treats the two as the same, so that condemning one appears to condemn the other.

Animals aren't consciousEthics & Morality

The argument slides between two meanings of 'conscious'. It asserts that animals are not conscious at all, meaning they have no experience. When challenged, it falls back to claiming they lack human-level consciousness, meaning self-reflection or empathy. The first claim would rule out suffering. The second, even if true, does not, yet it is used as though it carried the same weight.

There's nothing wrong with it if the animal is treated wellEthics & Morality

'Humane' shifts between 'causing less suffering than another method' and 'morally acceptable'. The first is a measurable comparison; the second is the conclusion being argued for.

Animal agriculture is only 4% of emissionsEnvironment

A national, direct-emissions-only figure is presented as though it answered a question about global, full-lifecycle impact. The number is accurate for a question nobody asked.

Plant protein is incompleteHealth & Nutrition

'Incomplete' is used as though it meant 'missing an amino acid', when in nutrition it means 'present in a lower proportion'. The alarming conclusion only follows on the first reading, while the evidence only supports the second.

Soy gives men estrogenHealth & Nutrition

Treats 'oestrogen' as one substance, when phytoestrogens and human oestradiol differ in structure, receptor affinity and physiological effect.

Veganism isn't healthyHealth & Nutrition

Slides between two different claims: that a vegan diet needs planning and supplementation, which is true, and that it is therefore unhealthy, which does not follow from needing planning.

There are compounds in animal foods you can't get anywhere elseHealth & Nutrition

Slides between three different claims: that a compound is found only in animal foods, that it can only be obtained from them, and that it is required from them. Only the first is established, and only the third would matter.

Animals don't have rightsPhilosophy & Logic

'Rights' moves between legal status and moral entitlement. The claim is true on the first reading and is the thing being argued about on the second, and it draws its force from running them together.

There's senseless suffering and there's meaningful sufferingPhilosophy & Logic

The argument draws on 'meaningful suffering' in the sense of suffering that has meaning for the person enduring it, such as a patient's recovery or a parent's sacrifice. It then applies the phrase to animal suffering whose only purpose is someone else's meal, as though the same sense carried over.