Swift's characters often know things they wish they could forget, a recurring theme that solidifies the line between innocence and guilt in Waterland. One could argue that Tom Crick, an historian, is cursed with knowledge -- he is part of a profession that exists primarily to uncover the forgotten past. Dick Crick on the other hand is blessed with ignorance. "[Dick] possesses those amnesiac, those time-erasing qualities so craved by guilty parties." (p.101) Only when Tom helps Dick to understand some of the secrets of the past does Dick lose control and run away to disappear forever.
Henry Crick, father of Tom and (presumably) Dick, embodies a fear of knowledge. Upon discovering the dead body of Freddie Parr floating in his lock, Henry turns away and counts to ten. "I knew what he was doing," says Tom, "He was hoping that all this was not happening." (p.21) If Henry had never known the body was there he would not have to worry about his own feelings of guilt. He vocalizes this fear of dangerous knowledge when he discovers Tom attempting to teach the "potato-head" Dick how to read: "Don't educate him! Don't learn 'im to read!" (p.28) Henry knows about the diaries left by his father-in-law Ernest Atkinson. He knows that Dick is not his son but Ernest's son by Helen, Henry's wife. And Henry wants to protect Dick from this knowledge, a classic case of "what you don't know can't hurt you."
The same problem exists for Tom in regard to the death of Freddie Parr. Tom thinks that Dick is the murderer but does not want to admit this to himself. When the inquest into the death of Freddie declares "Accidental Death" as the cause, Tom is overjoyed. "It's all right," he says to Mary, "Accidental death. So it's all right. All right. Nothing's changed." Mary responds, "It's not all right. Because it wasn't an accident. Everything's changed." (p.99) Tom throws a temper tantrum at Mary's refusal to deny her knowledge of events. The courts had neatly allowed him to forget about what really happened, allowing life to continue normally, and Mary has ruined that. Her knowledge precludes Tom's innocence.
There are even times when an entire society wants to forget. For Swift's characters, the two world wars are just this type of event. When Ernest Atkinson converts Kessling Hall into a mental hospital for war victims, the town of Gildsey reacts not with thanks but with uneasiness: "there's something the people of Gildsey (and not just them but people everywhere) wanted to do more than forgive; and that was forget." A war is a very difficult thing to forget, but if you could forget the war would that change anything? This is an important aspect of Swift's philosophy. For if you forget (or never knew) that something happened did it really happen at all? This issue is discussed at length in the short story "Hoffmeier's Antelope." On an individual level, this may be true. If Dick had never been told the identity of his true father then Henry Crick would have been his real father. But it is impossible for an entire society not to "know" that a war has occurred, there are too many reminders (and veterans). And of course, history will not let us forget. One of the reasons for this is precisely so that we do not forget about things like the Holocaust. So that they will never happen again.
Henry's personal reaction to the war is indicative of Swift's philosophy. "Henry Crick forgets. He says: I remember nothing. Bur that's just a trick of the brain. That's like saying: I don't care to remember, and I don't want to talk about it. Yet it's perfectly natural that Henry Crick wants to forget, it's a perfectly good sign that he thinks he's forgotten, because that's how we get over things, by forgetting." (p.168) Tom Crick re-asserts this belief in relation to the mental lapse of his wife Mary: ". . . perhaps amnesia's best, perhaps amnesia's the cure for all. . ." (p.249)