I wrote this for the local hackerspace mailing list because people have been increasingly making value judgments about other people's projects.
Some people think all development should stop before we turn everything into gray goo. Others have a limited list of approved problems that people can work on. While others say you can work on whatever you want.
All three care about the future: the first views technology as a means to tempt and harm on a even greater scale; the second sees the world as resource-limited and wishes to make others work on their problems; the third looks at the past, notes the existence of much chaotic cross-fertilization, and votes for more.
All three can reasonably justify their views. The future of the world just asks you to be aware that you are giving up the other two when you choose one.