In my humble opinion, you are totally correct about the first argument and Cowen and Parfit are totally correct about the second argument. (Note: I haven’t read the paper just your post).
1.
The first argument is philosophy. If a person genuinely believes that a state has a greater duty to its current citizens today than to future citizens then that person should probably apply a social discount. All that can be done to counter a philosophical intuition is to point out that there are intuitions that would suggest otherwise, clearly unpersuasive to someone who doesn’t share your intuitions you.
That said I think the Cowen and Parfit argument could be stronger by pointing out the mutual benefits or intergenerational trade, our place in history and how much we benefit form forward thinking ancestors, and the benefits to us of planning long term.
2.
Cowen and Parfit are correct this is not a case of double counting. The whole point of a social discount rate is to allow your economic models to map your goals. So the fact they align with your goals is not double counting, it is just counting. It would be like claiming that if I would intuitively buy tasty food, then decided to build a model to map out my preferences, I should discount the value of nice tastes because I already consider nice tastes. Which is rubbish as I would just end up using the model (rather than my intuition) to choose what to buy and then having less nice tasting food than I would ideally like.
Now you can use discounts to adjust for biases. For example if you know you always overestimate the value of tastiness of food compared to other factors, even after applying your model, then you could apply a factor to try to counter this intuition. (Real world example even after applying models people underestimate construction costs due to optimism bias etc so add a factor to increase estimated construction costs). But this is if you feel you have a bias that does not match your goals, even after using a model to make decisions. Making the case for this would require some empirical evidence that such a bias exists. But the evidence does not point in this way which leads to the second point that Cowen and Parfit raise that you do not discuss which is a key part of the argument.
All the evidence suggests that humans do not value the future as much as they would ideally like to. If anything an empirical examination comparing what we do for the future compared to what we want for the future should suggest (as Cowen and Parfit highlight) a negative discount rate, to push back against availability bias and political short-termism etc. (eg see: https://www.bbc.com/future/article/20190318-can-we-reinvent-democracy-for-the-long-term)
In my humble opinion, you are totally correct about the first argument and Cowen and Parfit are totally correct about the second argument. (Note: I haven’t read the paper just your post).
1.
The first argument is philosophy. If a person genuinely believes that a state has a greater duty to its current citizens today than to future citizens then that person should probably apply a social discount. All that can be done to counter a philosophical intuition is to point out that there are intuitions that would suggest otherwise, clearly unpersuasive to someone who doesn’t share your intuitions you.
That said I think the Cowen and Parfit argument could be stronger by pointing out the mutual benefits or intergenerational trade, our place in history and how much we benefit form forward thinking ancestors, and the benefits to us of planning long term.
2.
Cowen and Parfit are correct this is not a case of double counting. The whole point of a social discount rate is to allow your economic models to map your goals. So the fact they align with your goals is not double counting, it is just counting. It would be like claiming that if I would intuitively buy tasty food, then decided to build a model to map out my preferences, I should discount the value of nice tastes because I already consider nice tastes. Which is rubbish as I would just end up using the model (rather than my intuition) to choose what to buy and then having less nice tasting food than I would ideally like.
Now you can use discounts to adjust for biases. For example if you know you always overestimate the value of tastiness of food compared to other factors, even after applying your model, then you could apply a factor to try to counter this intuition. (Real world example even after applying models people underestimate construction costs due to optimism bias etc so add a factor to increase estimated construction costs). But this is if you feel you have a bias that does not match your goals, even after using a model to make decisions. Making the case for this would require some empirical evidence that such a bias exists. But the evidence does not point in this way which leads to the second point that Cowen and Parfit raise that you do not discuss which is a key part of the argument.
All the evidence suggests that humans do not value the future as much as they would ideally like to. If anything an empirical examination comparing what we do for the future compared to what we want for the future should suggest (as Cowen and Parfit highlight) a negative discount rate, to push back against availability bias and political short-termism etc. (eg see: https://www.bbc.com/future/article/20190318-can-we-reinvent-democracy-for-the-long-term)
Hope that helps.