Invoking the continuum fallacy is a silencing tactic in which someone asserts that a given action cannot constitute harassment, stalking, assault etc because there is not a bright line between such action and innocent actions, or between such an action done once and doing it sufficiently often to be abusive.
For example, unwelcome sexual attention is harassment, but in some circumstances, it might be appropriate to briefly express sexual attraction by eg asking someone out, finding out the invitation is unwanted, and leaving it there. (Needless to say: very context dependent, eg, not at a conference in an elevator at 4 in the morning to someone who has very recently spoken publicly about finding all sexual attention at conferences unwelcome.) It becomes the continuum fallacy when someone argues that repeated such invitations, invitations in certain contexts where they're out of place, single invitations that are sufficiently threatening and so on, cannot possibly constitute harassment (or that harassment is an invalid concept) because the boundary between some brief communications which are ended as soon as they are known to be unwanted and communications which are harassment cannot be precisely defined.
Further reading
- aetherize applies the continuum fallacy to @elevatorgate harassment and stalking defences in John Scalzi's blog comments
- Wikipedia: Continuum fallacy
