Galileo uses apples as a demonstrative aid in his lessons and as a symbol of forbidden knowledge. While teaching Andrea about Copernicus’ model of the universe, Galileo uses an apple to represent the Earth. After the demonstration, Andrea takes the apple to use in a demonstration of his own to convince his mother of the truth of Galileo’s ideas. Thus, the apple is a physical method of transmitting knowledge. Later, the apple takes on a more abstract dimension. When the Little Monk becomes captivated by Galileo’s writings (which he had considered heretical only moments before), Galileo refers to the document as “an apple from the tree of knowledge” that the monk has “got to wolf down,” even though it might mean damnation. In his later life, Galileo demands that Virginia cook all of his food with an apple, be it duck or liver with onions. In each instance the apple takes on the same symbolism that it has in Christian iconography: the forbidden knowledge with which Satan tempted Eve. For Andrea, the apple (which represented Earth orbiting the Sun) was a direct contradiction of the Church’s teachings. For the Little Monk, the apple symbolized forbidden knowledge that, once tasted, could not be repressed. Galileo’s later obsession with apples in his food is proof that he never abandoned his earlier pursuit of forbidden knowledge, but instead kept it covertly wrapped up in other writings (the way he tucks apples into his liver and onions).
The The Life of Galileo quotes below all refer to the symbol of Apples. For each quote, you can also see the other characters and themes related to it (each theme is indicated by its own dot and icon, like this one: Note: all page numbers and citation info for the quotes below refer to the Penguin Books edition of The Life of Galileo published in 2008.).
The timeline below shows where the symbol Apples appears in The Life of Galileo. The colored dots and icons indicate which themes are associated with that appearance.
...Mrs. Sarti leaves, Galileo again tries to demonstrate to Andrea. This time, he uses an apple to represent the Earth. Andrea, however, doesn’t like Galileo using these sorts of examples, as... (full context)