From “Phantasmatic Fissures: Spider“ by Patricia MacCormack:
David Cronenberg’s Spider (2002) is a film about the tentative and risky world of memory. … Viewing film is a practice that involves the coalescence of phantasy and memory. The memory of viewing – like Spider’s memory – does not always present an authentic or reliable version of what we have seen. But this transgression is not a flaw or failure at truth and authenticity. Cronenberg’s film is about versions of memories rather than, and occasionally opposed to, actualities of history.
From Mark Fisher’s blog entry “She’s Not My Mother”:
While this seems to be the preferred interpretation, the film does not close down any of the narrative possibilities it has opened up . I think we can enumerate nine distinct narrative options that the film leaves open:
[SPOILER SPACE: Drag your mouse pointer across the space below.]
Bill killed his wife, and he really did co-habit with a prostitute called Yvonne.
Bill did kill his wife, there really is an Yvonne, but she never moved in with Spider’s father.
Bill killed his wife, but there is no such a person as Yvonne.
Spider, not Bill, killed his mother, but Bill moved in with Yvonne after his wife’s death.
Spider killed his mother, there is a prostitute called Yvonne, but she never moved in with Spider’s father.
Spider killed his mother, and there is no such person as Yvonne.
Neither Spider nor Bill killed Mrs Cleg, but Bill moved in with Yvonne after his mother’s death.
Neither Spider nor Bill killed Mrs Cleg, there really is an Yvonne, but she never moved in with the Clegs.
Neither Spider nor Bill killed Mrs Cleg, and there is no such person as Yvonne.
From Dennis Grunes’s blog entry on the film:
In other words, to see this film is to find oneself, metaphorically, inside Cleg’s damaged, dissolved and dissolving mind, along with what turns out to be a host of horrific childhood memories—although here, also, the match-up of “memories” and realities proves to be indistinct.