the efficiency of love

Isn't it ridiculous that man--so intelligent and hardworking and proud--still could not figure out a single explanation for the occurence of love. They say that that which you cannot measure, you cannot know. True? We are able to comprehend by putting the intended subject within our own horizon of comprehension. If we cannot grasp it as a whole, then we cannot know it. And so love, along with so many other things, is left in the darkness. But even so, we use love for so many things, in so many ways, as if it is what gives us life. How come love can be a measure of so many things, when love itself cannot be measured?