Hogfather - Mental Shields

'Just shut up, please, don't gabble,' said Susan. ‘I didn't mean death, I meant Death with a capital D. I remember things that haven't happened yet and I Can TALK THAT TALK and stalk that stalk and ... if he gets sidetracked, then I'll have to do it. And he does get sidetracked. I don't know what's really happened to the real Hogfather or why Grandfather's doing his job, but I know a bit about how he thinks and he's got no ... no mental shields like we have. He doesn't know how to forget things or ignore things. He takes everything literally and logically and doesn't understand why that doesn't always work----'

She saw his bemused expression.

'Look ... how would you make sure everyone in the world was well fed?' she demanded.

'Me? Oh, well, I...' The oh god spluttered for a moment. 'I suppose you'd have to think about the prevalent political systems, and the proper division and cultivation of arable land, and---'

'Yes, yes. But he'd just give everyone a good meat' said Susan.

'Oh, I see. Very impractical. Hah, it's as silly as saying you could clothe the naked by, well, giving them some clothes.'

'Yes! I mean, no. Of course not! I mean, obviously you'd give- oh, you know what I mean!'

'Yes, I suppose so.'

'But he wouldn't.’

***

Hogfather - p192