Tobias asked: “Can I conclude that the tree is made of vanna rupa because a tree is something visible?”
No. The tree is made of four great elements: patavi, apo, tejo, vayo. OR, in terms of modern science, a tree is made of atoms/molecules.
– Vanna rupa is the “picture of that tree registered in one’s mind.
“As I understand external rupa make contact with the internal rupa”.
Yes, but the contact is not directly made with the external rupa (in our example, the tree).
– The contact (phassa) is made between the vanna rupa (the picture captured with the aid of eyes) and the internal rupa, which is the cakkhu pasada rupa that is in our mental body (gandhabba).
– That contact (phassa) can become a “defiled contact” (samphassa) if one’s greedy gati automatically incorporated by the mind; see, “Difference between Phassa and Samphassa“.
“The eye for example comes in contact with photons. But the tree is not made of photons. ”
No. The photons (light) just help in capturing an image of the tree by the eyes. Then the eyes pass that captured image to the brain. The brain processes that information and passes it along to the cakku pasada in the mental body.
– That last step is when the “contact” (phassa) is made and the cakkhu vinnana arises.
– This is stated in “cakkhunca paticca rupeca uppaddati cakkhu vinnanam”. Here “cakkhu” is cakkhu pasada rupa. “Rupa” is the signal of the image received by the cakkhu pasada rupa. Cakkhu vinnana is the overall “mental defiled consciousness” of that external rupa (in our case, the tree).
-That cakkhu vinnana is automatically contaminated with our gati (if we had any liking for that tree or even if just seeing the tree generated a liking for that tree).