The Open Thread posted at the beginning of the month has gotten really, really big, so I've gone ahead and made another one. Post your new discussions here!
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
"How much will it cost?" "How long will it take?" Who the hell is supposed to be able to answer that on a basic research problem?
These questions are for public proposals, not for someone considering a project by themselves. If you're building a collider or wish to play with someone else's collider, you'd better know how much it will cost and how long you'll take.