# How did Newton guess that the answer to the 3-dimensional “kissing problem” is 12?

I understand almost nothing about sphere packings and kissing numbers, but I am very curious to learn about the Newton - Gregory discussion of the problem. In particular, I wonder if Newton's guess was a "blind guess" or an educated guess with a certain logic behind it. So if someone knows a good article that focuses on the Newton - Gregory discussion please give a link.