not that much to things

[engee30]

How can I interpret the words in the second sentence of the extract below:

Why do you have to know so much about things, Jessie? There's not that much to things that I could ever see.

Should I think like this, I can't explain everything to you because there are a lot of things I don't understand either?

[mykwyner]

It is difficult for me to be certain without the complete text, but it sounds to me like the word things, in this case, means material possessions as opposed to nature or ideas. Try substituting another noun, like automobiles, drugs or mathematics instead of things and the sentence will make sense to you.