[This question is a cross post from chemistry](https://chemistry.stackexchange.com/questions/3972/how-do-the-molecules-know-the-future-how-do-they-proceed-to-form-most-stable/). I'm not very convinced with the answer there. So, I'm posting it here.

I'm tutoring few students for Chemistry. During the course, I many times use the phrase "Out of these possibilities this one is stable. So it is formed". I get questions like, "How do the molecules know?"

Honestly I don't know. How do they proceed to form "Most Stable" compound?