Atheism is not a belief!!

[Silver]

According to John they really know nothing about the 'sun thing', so why does Jane assume it's hot?

From the complicated to the ridiculous. They have no idea the sun is hot like fire is, they have not used the sun to cook with.

Simple deduction would allow one to know that the sun is hot. When the sun is in the sky, one feels the sun's warmth on one's skin. When the sun goes away, the warmth eventually dissipates until the sun rises once again to bring along with it the warmth and heat.