[mkolodny]

From your linked article:

> The fallacious sense of "slippery slope" is often used synonymously with continuum fallacy, in that it ignores the possibility of middle ground and assumes a discrete transition from category A to category B. In this sense, it constitutes an informal fallacy.

"If you take N steps, you will take N+1 steps" is a fallacy whenever it's possible that you won't take N+1 steps.

[HPsquared]

Not what was said. What was said: if you DON'T take the Nth step, you then WON'T take the N+1 step.

"Not A -> Not B" is different logic than "A -> B". A is necessary but not sufficient for B.