Nothing comes from nothing. Take that as a given. But a mountain's coming from molehill[note 1], while not literally a case of something from nothing, would be just as bad. There is a Polish proverb that even Solomon cannot pour a drink from an empty container. But, likewise, even Solomon cannot pour wine from a container of water (at least without help from something greater than Solomon). The more doesn't come from the less.
What doesn't have something cannot give it.
Now, obviously, this principle needs to be limited. You can get a headache from playing a videogame for too long, but the videogame doesn't have a headache. The principle applies to positive being, to perfections.
So our causes must have all the perfections we have. It is plain, then, that the cause of humanity must have all the perfections of thought and will that humanity has. The First Cause cannot simply be a bunch of energy or matter. This is obviously important for the second part of the Cosmological Argument, the move from a First Cause to God. And of course, this is a very familiar line of thought. It's very forcefully there in Samuel Clarke, and it was already there in the medievals (whom Clarke amusingly criticizes while recapitulating their arguments).
But I don't want to dwell on the consequences of the principle that nothing can give what it doesn't have. Rather, I want to say something about the line of thought, if one may call it that, that leads me to it this morning. There is nothing really new here. The line of thought is one I had been thinking about for years, partly under the influence of Richard Sisca. But suddenly this morning it becomes very plausible. One is told that on big things people aren't convinced by argument, but rather have something like a conversion. But one can also have something like a conversion with regard to an argument. Suddenly it becomes clear that the line of thought is just right, and that the objections to it are mere technicalities. Sometimes one even has the experience of thinking that one knew this all along—or at least that one should have. This is a very interesting experience.