The general argument is one of net suffering. The trouble is that weird things happen when you try to assign values to suffering, add those together across multiple agents, etc. On the one hand, we should avoid scope insensitivity. On the other hand, the assertion that adding up 3^^^3 dust specs is worse than 50 years of torture packs in quite a few other assertions (that suffering should be added linearly across all agents and all types of suffering, for one).
The general argument is one of net suffering. The trouble is that weird things happen when you try to assign values to suffering, add those together across multiple agents, etc. On the one hand, we should avoid scope insensitivity. On the other hand, the assertion that adding up 3^^^3 dust specs is worse than 50 years of torture packs in quite a few other assertions (that suffering should be added linearly across all agents and all types of suffering, for one).