Now as they went out of Jericho, a great multitude followed Him. And behold, two blind men sitting by the road, when they heard that Jesus was passing by, cried out, saying, “Have mercy on us, O Lord, Son of David!” Then the multitude warned them that they should be quiet; but they cried out all the more, saying, “Have mercy on us, O Lord, Son of David!” So Jesus stood still and called them, and said, “What do you want Me to do for you?” They said to Him, “Lord, that our eyes may be opened.” So Jesus had compassion and touched their eyes. And immediately their eyes received sight, and they followed Him. (Matthew 20:29-34)
Two thoughts on sight offered by St Gregory of Nyssa which also give us some sense of how they understood eyesight in the 4th Century. In the first comment, Gregory refers to a scientific explanation of sight. This is important to note – the learned in the ancient world did not reject science and did not rely on superstition to explain things. They relied on the science of their day to establish truth about the world. Many of the great ancient thinkers did believe the eye somehow emitted a ray that allowed a person to see things. But if this were true, why couldn’t people see at night? So they reformed their thought to recognize that there was some combination of light from an external source and the work of the eye which allows us to see things. In this first quote of Gregory he is referencing that you sometimes can see a reflection of what a person is looking at in their eyes (pupils).
We see faces in the clear pupils of eyes that are focused on someone (for people who can give the scientific explanations of such things say that the eye activates its vision by receiving the impressions of the images given off by visible bodies)… (HOMILIES ON THE SONG OF SONGS, p 117)
Here Gregory seems to accept the idea that somehow visible things give an impression of themselves on the eye which then activates our vision and we see the thing impressing on our eye. This is the science of his day. It will be another 600 years after Gregory before the theory develops and is proven that vision occurs from light reflecting off an object into the eye which is what causes sight. It will be several centuries later before the physics of light is understood. My point here is only that the Church Fathers did accept and use the science of their day, which they did not learn from the Bible. They accepted that scientific truths exist which the Bible does not provide us, but which are important for understanding the world we live in. They had no problem with truth coming from sources other than the Bible and that the Bible not only did not provide us with all the truth of the world, but occasionally the Bible contradicted a truth known from science. When that happened, they were very cautious about dealing with the contradiction and thought the problem was our understanding of the world or the Bible is just incomplete.
In the second quote of St Gregory, he is using sight to prove the existence of a soul or self which can see. What gets impressed on the eye would not have any meaning unless there is someone capable of interpreting it.
Do you see what your sight teaches you? it would not provide you with such understanding by its own power, if there were not something looking through the sense of sight which can use the things which come to perception as guides to penetrate through the appearance to that which does not appear. (ON THE SOUL AND THE RESURRECTION, p 40)
It is because there is a person (a soul or mind) which can understand what it sees that makes sight possible – sight, as modern science knows, is as much a product of the brain as of the eye. Seeing things can lead to greater unseen truths as our brains interpret what we see, sometimes giving us further ‘insight’. The perceptible world is also a world of mystery which ‘hides’ other truths which God has put there. Humans are gifted by God to uncover these truths. Through our experience of creation, we can come to some insights into God. Through icons we can see the spiritual and divine dimensions present in God’s saints and creation.
Fraternized 