Torture is not the obvious answer, because torture-based suffering and dust-speck-based suffering are not scalar quantities with the same units.
To be able to make a comparison between two quantities, the units must be the same. That’s why we can say that 3 people suffering torture for 49.99 years is worse than 1 person suffering torture for 50 years. Intensity Duration Number of People gives us units of PainIntensity-Person-Years, or something like that.
Yet torture-based suffering and dust-speck-based suffering are not measured in the same units. Consequently, we cannot solve this question as a simple math problem. For example, the correct units of torture-based suffering might involve Sanity-Destroying-Pain. There is no reason to believe that we can quantitatively compare Easily-Recoverable-Pain to Sanity-Destroying-Pain; at least, the comparison is not just a math problem.
To be able to do the math, we would have to convert both types of suffering to the same units of disutility. Some folks here seem to think that no matter what the conversion functions are, 3^^^3 is just so big that the converted disutility of 3^^3 dust specs is greater than the converted disutility of 50 years of torture for one person. But determination of the correct disutility conversion functions is itself a philosophical problem that cannot be waved away, and it’s impossible to evaluate that claim until those conversion functions have at least been hinted at.
One way to get different types of suffering to have the same units would be to represent them as vectors, and find a way to get the magnitude of those vectors.
The torture position seems to do the math by using pain intensity as a scalar. Yet there is no reason to to believe that suffering is a scalar quantity, or that the disutility accorded to suffering is a scalar quantity. Even pain intensity is case where “quantity has a quality all of its own”: as you increase it, the suffering goes through qualitative changes. For example, if just a 10% increase in pain duration/intensity causes Post-Traumatic Stress Disorder, that pain is more than 10% worse, and it’s because a qualitatively different type of suffering. The units change.
Suffering may well be better represented as a vector. Other dimensions in the vector might include variables such as chance of Post-Traumatic Stress Disorder (0 in the case of dust specks which are uncomfortable but not traumatic, and approaching 100% in the case of torture), non-recovery chance (0% in the case of dust specks, approaching 100% in the case of torture), recovery time (<1 second in the case of dust specks, approaching infinity in the case of 50 years of torture), insanity, human rights violation, career-destruction, mental-health destruction, life destruction...
Choice of pain intensity only over other variables relevant to suffering is begging the question. We could cherry-pick another dimension out of the vector to get a different result, such as life destruction. LifeDestructionChance(50YearsOfTorture) could be greater than LifeDestructionChance(DustSpeck) * 3^^^3 (I might be committing scope insensitivity saying this, but the point is that the answer isn’t self-evident). Of course, life destruction isn’t the only relevant variable to the calculation of suffering, but neither is pain intensity.
Now, if there is a way to take the magnitude of a suffering vector (another philosophical problem), it’s not at all self-evident that Magnitude( SpeckVector ) * 3^^^3 > Magnitude( 50YearsOfTortureVector), because the SpeckVector has virtually all its dimensions approaching 0 while the TortureVector has many dimensions approaching infinity or their max value (which I think reflects why people think torture is so bad). That would depend on what the dimensions of those vectors are and how the magnitude function works.
But determination of the correct disutility conversion functions is itself a philosophical problem that cannot be waved away, and it’s impossible to evaluate that claim until those conversion functions have at least been hinted at.
You seem to have gotten hung up on 3^^^3, which is really just a placeholder for “some finite number so large it boggles the mind”. If you accept that all types of pain can be measured on a common disutility scale, then all you need is a non-zero conversion factor, and the repugnant conclusion follows (for some mind-bogglingly large number of specks). I think that if a line of argument that rescues your rebuttal exists, it involves lexicographic preferences.
Torture is not the obvious answer, because torture-based suffering and dust-speck-based suffering are not scalar quantities with the same units.
To be able to make a comparison between two quantities, the units must be the same. That’s why we can say that 3 people suffering torture for 49.99 years is worse than 1 person suffering torture for 50 years. Intensity Duration Number of People gives us units of PainIntensity-Person-Years, or something like that.
Yet torture-based suffering and dust-speck-based suffering are not measured in the same units. Consequently, we cannot solve this question as a simple math problem. For example, the correct units of torture-based suffering might involve Sanity-Destroying-Pain. There is no reason to believe that we can quantitatively compare Easily-Recoverable-Pain to Sanity-Destroying-Pain; at least, the comparison is not just a math problem.
To be able to do the math, we would have to convert both types of suffering to the same units of disutility. Some folks here seem to think that no matter what the conversion functions are, 3^^^3 is just so big that the converted disutility of 3^^3 dust specs is greater than the converted disutility of 50 years of torture for one person. But determination of the correct disutility conversion functions is itself a philosophical problem that cannot be waved away, and it’s impossible to evaluate that claim until those conversion functions have at least been hinted at.
One way to get different types of suffering to have the same units would be to represent them as vectors, and find a way to get the magnitude of those vectors.
The torture position seems to do the math by using pain intensity as a scalar. Yet there is no reason to to believe that suffering is a scalar quantity, or that the disutility accorded to suffering is a scalar quantity. Even pain intensity is case where “quantity has a quality all of its own”: as you increase it, the suffering goes through qualitative changes. For example, if just a 10% increase in pain duration/intensity causes Post-Traumatic Stress Disorder, that pain is more than 10% worse, and it’s because a qualitatively different type of suffering. The units change.
Suffering may well be better represented as a vector. Other dimensions in the vector might include variables such as chance of Post-Traumatic Stress Disorder (0 in the case of dust specks which are uncomfortable but not traumatic, and approaching 100% in the case of torture), non-recovery chance (0% in the case of dust specks, approaching 100% in the case of torture), recovery time (<1 second in the case of dust specks, approaching infinity in the case of 50 years of torture), insanity, human rights violation, career-destruction, mental-health destruction, life destruction...
Choice of pain intensity only over other variables relevant to suffering is begging the question. We could cherry-pick another dimension out of the vector to get a different result, such as life destruction. LifeDestructionChance(50YearsOfTorture) could be greater than LifeDestructionChance(DustSpeck) * 3^^^3 (I might be committing scope insensitivity saying this, but the point is that the answer isn’t self-evident). Of course, life destruction isn’t the only relevant variable to the calculation of suffering, but neither is pain intensity.
Now, if there is a way to take the magnitude of a suffering vector (another philosophical problem), it’s not at all self-evident that Magnitude( SpeckVector ) * 3^^^3 > Magnitude( 50YearsOfTortureVector), because the SpeckVector has virtually all its dimensions approaching 0 while the TortureVector has many dimensions approaching infinity or their max value (which I think reflects why people think torture is so bad). That would depend on what the dimensions of those vectors are and how the magnitude function works.
You seem to have gotten hung up on 3^^^3, which is really just a placeholder for “some finite number so large it boggles the mind”. If you accept that all types of pain can be measured on a common disutility scale, then all you need is a non-zero conversion factor, and the repugnant conclusion follows (for some mind-bogglingly large number of specks). I think that if a line of argument that rescues your rebuttal exists, it involves lexicographic preferences.