Though phrased like a simile, this expression is the opposite of metaphorical. Not only does it not involve an imaginative comparison, it denies the very possibility of comparison. Anything you can imagine has to be based to some extent on something you have seen or imagined before.
And yet, though it is not metaphorical, it isn’t literal either. When someone says – to pick an example at random – that North Korea will experience “fire and fury like the world has never seen,” the understood meaning is opposite to what the words literally say: that is, the fire and fury will be very like fire and fury the world has seen before, but with greater fieriness and furiousness than in the past two administrations. So like doesn’t mean “similar to”; it just means >.
Thanks to my friend Gary Karasik, who suggested “Like nothing you’ve ever seen before!” as a tagline for Metaphor Awareness Month.
Photo: Unknown, “Portrait of Something Similar to Nothing”