A commonly heard criticism of germline genetic engineering is that the modifications made to genome would be permanent and would therefore affect all future offspring in the genetic lineage making it an exceptionally dangerous proposition. Those of us in favor of germline genetic engineering are then considered to be profoundly thoughtless to believe that we have the present knowledge to make judgements about what are the correct genetic modifications that could affect countless future generations. Our ignorance about the right modifications and their long-term consequences should then caution us against germline genetic engineering.
But our inability to predict all long-term, multi-generation consequences of germline modifications is not an indisputable argument against doing it. Firstly, the argument that germline modifications would necessarily be permanent is clearly false. Genetic modifications to the germline can be reversed using the same techniques that put them there in the first place. Additionally, it is worth remembering that progress in genetic engineering techniques is hardly going to stop, just look at the pace at which CRISPR has revolutionized the field. Future generations will have ample ability to revise past modifications and improve upon them.
It is also perfectly reasonable to believe that the modifications we consider to be beneficial today will continue to be considered so by future generations. The fact that potential changes made today may end up being permanent by choice is no more a serious argument against deliberate germline modification than it would be against the previous germline modifications caused by natural selection. If modifications we make today give future generations a reduction in the risk of Alzheimer’s or cancer or increase their intelligence and it happens that they chose to maintain these modifications permanently I can’t see that as reason for disappointment.
Nevertheless, just because future generations will have the means to reverse changes doesn’t mean we should be carefree about what changes we make. For example, it sounds like a good idea to reduce our tendencies for violence, anger and aggression, but doing so excessively could lead to individuals who are exceedingly willing to submit to authority and unable to muster any resistance to injustice. Aldous Huxley envisioned a similar scenario in Brave New World where humanity leads shallow, meaningless lives and has been conditioned to be entirely happy with their dismal circumstances and unable to resist. If such modifications were transferred perpetually then humanity could end up eternally imprisoned in that submissive and shallow existence.
We should therefore strive to make germline modifications that not only improve well-being but also expand humanity’s capacity to make further modifications intelligently. Germline modifications which provide increased longevity, improved memory, and greater intelligence are a few examples which would likely both result in an increase in human well-being but also an increase in our capacity to make further germline modifications intelligentlly.
In short, transhumanism’s call for a wise use of germline genetic engineering is actually a guard against Aldous Huxley’s Brave New World and not a path towards it.