eli5 : Mutually Exclusive


I’m sorry if this seems dumb. I tend to take things literally and “mutual” and “exclusive” seem to be antonyms but mutually exclusive is a term used a lot and it confuses the crap out of me. I’m a native English speaker also.

Does it mean that the two things CAN exist together? I feel like my brain does gymnastics trying to understand the term; I’m not a dumb person but this term just totally eludes me!

Please don’t attack me, just trying to not feel stupid.

In: 49

It means two things which cannot co-exist.

Hot snow, wealthy poor people, loud silence etc etc

Usually the phrase refers to attributes which can’t both be simultaneously true. “It’s a green light” and “it’s a red light” are mutually exclusive phrases (at least about the same light). “It’s a windy day” and “it’s a hot day” are not mutually exclusive.

The term “mutually exclusive” simply means that two things by definition cannot exist or coexist together or at the same time.

For example if you were to flip a coin getting heads is mutually exclusive with getting tails. The coin cannot land on both sides simultaneously.

These answers are all great. I think maybe it’s the “mutually” part that is confusing you. It just means that each element, by itself, *means* that the other one cannot be present. If a coin lands heads, that *means* it cannot simultaneously have landed tails. If a man is a bachelor, that *means* he cannot simultaneously be married. Each element of the expression excludes the other – they **both** have that property. They mutually exclude each other.

Mutually exclusive means that a excludes b, and b excludes a. They exclude each other mutually.

If I say you can have a pizza and the toppings can be pepperoni and sausage, sausage and peppers, pepperoni and ham, and ham and peppers, then that means that sausage and ham are mutually exclusive. You can can sausage on the pizza with another topping, but that excludes ham. You can also have ham with another topping, but the ham excludes the sausage.