I’ve been asked about “bad design.” “If we can observe ‘good design’ in the universe when we can also observe bad design. Why is about 85% of this planet uninhabitable for humans?? Isn’t that a glaring error when you think it was made for us? Why are there vestigial organs and junk DNA?”
I’m not sure what is meant by this argument. I’m pretty sure that more than 15% of the world is inhabitable. As for areas that are not, the ice caps are essential to our world, and if they melted (as global warming says they are in the process of doing) then the world would be drastically changed, and then largely uninhabitable. The caps are actually a great exhibit of how perfectly situated our planet is in our solar system. If we were any closer to the sun, earth would probably look a lot like Venus, hundreds of degrees hot and completely uninhabitable. If we were any further away, we would be frozen over like mars. But we are in just the right spot. Deserts also occur as a natural part of the way our world is.
Deserts receive less rain for various reasons, but this often has to do with the terrain surrounding it. Many deserts form on the backside of mountain ranges, where much precipitation falls and therefore there is none left over by the time the clouds travel overtop of the mountains and reach the desert area.
Oceans are also necessary, so you can’t argue that the earth is poorly designed because people can’t live under water.
Also, “uninhabitable by humans” does not mean completely uninhabitable. Even deserts and ice caps have their ecosystems and wildlife that suits the area.
So no, I don’t think it is a “glaring error” that this earth was made for us.
As for vestigial organs and “junk DNA,” I’m not sure there is such a thing. Sometimes science hasn’t discovered things yet. For example, recently the function of the appendix was discovered (it turns out that the appendix functions as part of the lymphatic and immune systems). Formerly it was thought to be functionless because there seemed to be no side-effects after having it removed. But that does not mean it is “junk.” No one would argue that the spleen is junk, even though it can be removed.
DNA is something that science still has a lot to learn about. I’m pretty sure scientists wouldn’t call any DNA “junk,” only DNA that we do not yet understand. That’s from the scientists perspective. And it is perfectly normal and even scientific to admit that there are some things we haven’t figured out yet, but are striving toward understanding. And this is not an “argument from ignorance.” Scientific inquiry is based on this very thing.