"assuming them" is correct and can be used in written English.
It is a phrase that means to accept or consider something as true without proof or evidence. Example: Assuming them to be innocent, the jury acquitted the accused of all charges.
In doing so, Anthony is assuming them himself.
I didn't account for seat interferences, assuming them to be relatively less important than aisle interferences".
Listeners routinely hailed them as Aunt Etta and Uncle Person, if not mistakenly assuming them to be husband and wife.
Almost everyone picks up a tormentor or two while growing up, and until lately psychological researchers have ignored such relationships — assuming them to be little more than the opposite of friendship.
In Born Digital: Understanding the First Generation of Digital Natives (375pp, Basic Books, £9.99), by contrast, John Palfrey and Urs Gasser have actually bothered to find out what young people do online, rather than just assuming them to be glazed, distracted skimmers.
Including the indigenous people in negotiations was perhaps an obvious idea in retrospect, but it was a radical one in a country where they have been ignored and marginalised for centuries and where many Argentinians are unaware of their very existence, assuming them to have been wiped out long ago.
Why are millennials not as purpose-oriented as many of us assume them to be?
Puppets who slip their strings, puppet masters who assume them: Malik and Rushdie, Malik's dolls and Malik.
There's no real evidence that any of these characters are the gender people assume them to be.
Far from trying to emulate their attempts to reconcile freedom and justice, we assume them to be irreconcilable.
There is no evidence that the majority are as dull and backward as the BBC assumes them to be.
