Cowen & Parfit's stubborn attachment to silliness

Tyler Cowen & Derek Parfit wrote the following a couple of decades ago.

 “Imagine finding out that you, having just reached your twenty-first birthday, must soon die of cancer because one evening Cleopatra wanted an extra helping of dessert.”

I can't. There is no Structural Causal Model compatible with the Scientific knowledge I possess which would enable me to 'find out' any such thing. If some Professor tells me this,  I will soon prove he is a fool or a knave.

Suppose it were an Angel or an Oracle. In that case, I'd ask for a miracle or the winning numbers to the lottery.

What I wouldn't do is blame Cleopatra. Instead, I'd be thankful I had 21 years of life because my Mom and her Mom and so on sacrificed so much for their kids.

 The idea that a future life should be worth the same as a present life seems innocent enough.

How is it innocent? If it is true and if people feel more affection for their flesh and blood than for others more distantly related, then nobody should give money to charity. Rather they should concentrate on maximizing the number of their descendants- which means giving them as much of an advantage as possible over their sexual competitors. If the earth can hold only a finite population at any given time, then pro-natalism would combine with Nationalism to create a Nazi type of World Order.

But combine it with Cowen’s other premises and you reach a stunning conclusion: (1) If wealth-plus is the largest driver of human well-being; and (2) if small changes in the current growth rate will lead to huge differences in the amount of global wealth-plus many years from now; and (3) if future people (who will vastly outnumber present people) are just as valuable as you and me; then the most important thing we can possibly do is maximize the sustainable rate of growth so that the majority of humankind—namely those yet-to-be-born—will have much more wealth-plus than they’ll have if we continue chugging along with our current, middling rate of growth.

Either the human race has an infinite life span- in which case it doesn't matter what we do, Total Utlility will always be infinity- or else it has a finite life span in which case pro-natalism- having as many babies as possible- is the way to go.

Cowen's 'wealth-plus' 'includes traditional measures of economic value, as would be found in gdp statistics, but also measures of leisure time, household production, and environmental amenities, as summed up in a relevant measure of wealth.”

Assuming these things (except for 'household production') are 'normal goods'- i.e. Demand for them increases as Income rises- this just cashes out as Income. So Cowen is saying 'If growth is the main driver of growth then small changes in the rate of growth will, over time, lead to big changes in the amount of growth'.
This is a tautology.

Some human beings can make other human beings. If every girl thinks that a baby she can have is just as important as her, she should just keep having babies and encourage her girl children and grandchildren to do the same. This does not mean all will survive. But that's the discovery process for what is 'sustainable' growth.