If you have one reason for doing something and I give you a second reason for doing the same thing, it seems only logical that two reasons are better than one and you're more likely to do it.
Hvis du har en grund til at gøre noget og jeg giver dig en anden grund til at gøre det samme virker det kun logisk, at to grunde er bedre end en og du er mere tilbøjelig til at gøre det.