The middle hieroglyph was unknown to him, but he guessed that the two at the left symbolized the sun. From his studies of Coptic, Champollion knew that the Egyptian word for "sun" was pronounced rah. He wrote down the first two letters of that sound, RA. Next he put a question mark for the unknown middle hieroglyph. Then, at the end, he wrote SS, the sound of the last two hieroglyphs.

He studied the combination: RA ? SS. Suddenly he remembered a famous pharaoh whose name appeared in ancient Greek chronicles and also in the Biblical Book of Exodus: Rameses, or Ramesses. Could this be a hieroglyphic representation of Ramesses' name?

The details in the excerpt point to which big-picture idea?

Hieroglyphs are both a representation of sounds and symbols.
Several famous names can be found in the Biblical Book of Exodus.
The sun has symbolic meaning in many different cultures.
Champollion knew that the Egyptian word for “sun” was pronounced rah.