Well, I don't think Dent's heart is mentioned in the Hitchhiker's books but still he has one. Why? Because he is a human being, and by default those have hearts

Well, I don't think Dent's heart is mentioned in the Hitchhiker's books but still he has one. Why? Because he is a human being, and by default those have hearts (although Adams could have made it otherwise). The general point is that inevitably works of fiction drag truths from the real world into the fictional one. Many things (and perhaps which Apple computer Dent had in particular) are neither true nor false in the relevant fictions, but that doesn't mean that inquiring whether they are is nonsensical or misguided.