Undistributed middle:

Formal Fallacy
Definition Example
When the middle general term in a categorical syllogism is not distributed to more specific terms of the same category. All humans are 2-legged, and all birds are 2-legged. Therefore all humans are birds.
In the example, the conclusion does not follow since it is 2-leggedness that is the larger more general category, encompassing both humans and birds, without either one of the smaller more specific categories encompassing the other. If one of the premises instead stated that all 2-legged things are birds, then the argument would be valid (but not sound).

Case Study One

Young people looking for social acceptance might argue to themselves “The cool wear sunglasses, and I’m wearing sunglasses. Therefore I’m one of the cool.”

Case Study Two

“All vampires are imaginary, and all gods are imaginary, so all vampires are gods.”

Keep in mind that a fallacious argument does not entail an erroneous position.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: