“We all want progress, but if you’re on the wrong road, progress means doing an about-turn and walking back to the right road; in that case, the man who turns back soonest is the most progressive.” -C. S. Lewis Many of you are a little bit skeptical that I talk about things like the History of the Universe, Inflation, Dark Matter and Dark Energy like they are absolute certainties. After all, isn’t it true that there are an awful lot of assumptions that we make in order for these things to be true? That’s right, I admit it. We make assumptions when we come up with these theories and pictures of how nature and the Universe themselves work. Perhaps it will be dark matter. Now, you know my position, and you also know that there are alternatives, despite their shortcomings. And perhaps there will be some great new discovery that invalidates one of the assumptions that went into it. And that’s true! If general relativity turns out to be wrong on large scales, maybe we actually are misinterpreting all of this data. But with the assumption that general relativity is correct, we get a whole suite of evidence that all points to dark matter. We have prec...