I think in certain contexts it makes sense to think about the closeness of two quantities in terms of percentage difference. For example, let’s say we’re not just talking about the numbers 98 and 100, but the rates 98 mph and 100 mph. When we talk about speed, what we’re actually interested in is usually not the speed itself but rather the amount of time it takes to cover a certain distance when traveling that speed.
So in this context, it makes sense to say that 98 mph is about 100 mph to the same degree that 980 mph is about 1000 mph—because they have the same marginal relation in the time required to cover a certain distance at those speeds.
This doesn’t follow. Epsilon is by definition arbitrary, therefore I could say that I want it to be 1 / 4^^^4 if I want to.
If we accept Eliezer’s proposition that the disutility of a dust speck is > 0, this doesn’t prevent us from deciding that it is < epsilon when assigning a finite disutility to 50 years of torture.