I came across this sentence:

"His memory was like that of a baby."

I was wondering why the possessive "baby's" wasn't used and why "baby" is acceptable whereas the possessive form is required in this sentence:

"Ian's car was like that of his."

marked as duplicate by FumbleFingers, user140086, Mari-Lou A, choster, tchrist Jun 8 '16 at 23:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • This is a gentle reminder. Most of your questions are better fit for our sister site English Language Learners. As advised by other users, you need to go there and ask a question. But remember, your deleted question on "conjunction" is off-topic on ELL, too. Do not ask off-topic questions here. – user140086 Jun 8 '16 at 5:57

The possessive is acceptable in your examples, in which case they mean

His memory was like a baby's memory.
Ian's car was like his car.

However, English accepts the so-called double possessive in which this elision doesn't apply:

She is a friend of my sister's.
John is a fan of hers.

It's redundant since of, -'s, and possessive pronouns all signify the genitive, but language isn't necessarily logical. The form has its use in distinguishing

A picture of my family

which is a portrait of your relatives and

a picture of my family's

which is a picture your family owns.

We generally reserve the doubled possessive for human beings, like babies and sisters, but not otherwise. No one says

the founder of the country's.

Not the answer you're looking for? Browse other questions tagged or ask your own question.