The parallel to curing cancer was mainly drawn from this paragraph:
I could've become a doctor. All signs pointed to me likely being a very good one. In doing so, I would have gone to work and done my best to save lives every day. In that context, how is some programming environment a greater contribution to the world? Truthfully, it wouldn't be if I just set out to build an IDE. But that's not what I did - Light Table is just a vehicle for the real goal. While an IDE probably won't directly save someone's life, the things people are able to build with it could do exactly that.
To your main point:
If a new "text editor" ends up providing us a much more efficient means of creating things like Watson, in what way is that not just as important as curing any one disease?
Absolutely. I'm not arguing its importance, I'm arguing its effectiveness at achieving a mission, which I interpreted as curing cancer / saving lives. If you "increase everything by 1%", that is fantastic! And it has furthered many different missions 1% closer to their goals. This is very much important and necessary to the advancement of society, but its mission specifically should be put into context.
A microscope is a fundamental tool to help scientists do their best work. Thus, a person setting out to build one, in my opinion, has the opportunity to profoundly impact science's understanding of the human body and the world we live in. This understanding, further, can help scientists achieve their missions of curing disease, et cetera. But while the microscope plays a very important role in science, I believe it is unfair to the scientists for the microscope maker to believe that he is accomplishing his mission of curing disease by inventing one. Rather, he should be achieving his mission of helping our understanding of science, and/or furthering the missions of his users.
