[There's a pause. Ah, yes, getting weighed down by items. It's a bit of a new concept to Philip, what with hardly leaving the basement and not having many personal possessions in the first place.]

You could just as easily borrow books from the local library, I am assuming. That way you needn't carry them along with you.

[He would have suggested just getting rid of the things Karkat's already read, but... This kid had been weird about books last time. Might not have taken that well.]

I hope that it helps, though I imagine results will be limited if it is in fact a behavioral issue or an inclination of the species.