Question about which is the correct phrase

[FemaleCuckold]

I've written a paper and am trying to decide on a title. Well, actually, I already have the title, but I need to use the correct form of an expression.

Is the phrase supposed to be "One and the same" or "One in the same?"

If it makes a difference, the title is "Why Art and Craft Are Not One and/in the Same."

Google produces significantly more results for the "in" version, but some sources said it's really supposed to be "and" but people have modernized the expression to use "in." It seems to me using "and" would be the grammatically correct way.. but expressions are kind of tricky.

So which one should I use?

[lovely864md]

And.

[newtothis]

And. No doubt.

[cantnokdahustle]

It doesn't matter. Lexicography is descriptive, not prescriptive. The use of "in" is used frequently and accepted enough. Yes, I have a problem with this, but such is language.

[AJ F]

It's grammatically supposed to be "and". Saying One in the Same is an idiom, much like saying "I could care less". Which if read literally doesn't make much sense (opposed to "I couldn't care less"), but there's a general acceptance of it within the English language.

[Tristan Needler]

Say and.

It bothers me immensely when people say "I could care less."

[Misstamara]

"Fully 4 Shizzle Your Nizzle " lol

[stayforawhile]

One in the same, is the correct phrase I believe.

[dtrzcin]

They are one. They are the same. They are one and the same.

[screamoutmyname]

http://www.wsu.edu/~brians/errors/oneinsame.html (http://www.wsu.edu/%7Ebrians/errors/oneinsame.html)

The old expression “they are one and the same” is now often mangled into the roughly phonetic equivalent “one in the same.” The use of “one” here to mean “identical with each other” is familiar from phrases like “Jane and John act as one.” They are one; they are the same.