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Walking trees …

Modern science helps us understand a puzzling miracle


In the Gospel of Mark, there is an intriguing account of how Jesus healed a blind man in a two-step process:

And He came to Bethsaida. And they brought a blind man to Him and begged Him to touch him. And He took the blind man by the hand and led him out of the town. And when He had spat on his eyes and had put His hands on him, He asked Him if he saw anything. And he looked up and said, I see men as trees, walking. And after that He put His hands again on his eyes and made him look up. And he was restored and saw all clearly’ (Mark 8:22–25).

walking tree

Bible-believing Christians have no problem with this miracle, as the Bible presents the Lord Jesus Christ as the One who, in the beginning, created the universe and all things in it, including human life, by the power of His Word (Genesis 1; John 1:1–3; Colossians 1:16). The Lord who could do one could certainly do the other. The only question that arises is why the cure was in two stages rather than just one.

At Creation, God did not need millions of years—the greater the power, the less the need for time. He could have created everything in an instant, but chose to take six days for a reason (Exodus 20:8–11). Likewise, Jesus could have healed this man in one step, as He did all the other blind people He healed, but on this occasion He chose to take longer. The two steps were only a few moments apart, not months, so there was no time for ‘natural healing’ to occur, and the details given show that it was not a case of psychosomatic or ‘hysterical’ blindness being relieved (see below). The fact that Jesus took two stages does not mean that He was limited to some non-supernatural means to do His creative miracle. Perhaps it was so that we would see a proof of inspiration through the medical details given by the human writer, Mark, but of which he could not possibly have known the significance—details which were similar to those experienced by the people mentioned below, who had regained their sight after many years of blindness.


Virgil was a 50-year-old man, blind from childhood, whose sight was restored in 1991 after a cataract was removed and a new lens implanted in one eye. His story is told by Oliver Sacks, Professor of Neurology at the Albert Einstein College of Medicine, New York, in his book An Anthropologist on Mars.1 When the bandages were removed, Virgil could see, but he had no idea what he was seeing. Light, movement and colour were all mixed up and meaningless; all were just a blur. His brain could make no sense of the images that his optic nerve was transmitting. Although he now had eyesight, he was still mentally blind—a condition of perceptual incapacity known medically as agnosia.

Virgil could read the third line on a standard Snellan eye chart, equivalent to a visual acuity of about 20/100 (with a best of 20/80).2 However, he could not distinguish words, even though he could read Braille fluently, as well as raised or inscribed letters; he could easily read the inscribed letters on tombstones by touch. A cat was particularly puzzling, as he could see parts clearly—a paw, the nose, the tail—but the cat as a whole was only a blur, as were human faces. At the zoo, Virgil found it difficult to identify animals, and did so either by their motion or by a single feature, e.g. a kangaroo because it hopped, a giraffe because of its height, a zebra because of its stripes, and lions because of their roar. A few days after his operation, Virgil said that ‘trees didn’t look like anything on earth,’ but a month later he finally put a tree together and realized that the trunk and leaves formed a complete unit.

Clinical aspects

old man

People who have formerly been used to a world they accessed only by touch, hearing, taste, and smell tend to be baffled by ‘appearance’ which, being optical, has no correlation in the other senses. People who have been totally blind from birth (congenital blindness) or early childhood have lived in a world of time alone, not time and space. Thus the step at the end of a porch is something which occurs for a blind person a short time after he leaves the doorway, rather than something he is aware of in space. Sacks quotes the autobiography (Touching the Rock) of John Hull, a blind man, who says that, for the blind, people are there only when they speak; they come and they go out of nothing.

Sighted babies learn to master all this as time goes by, an achievement, it should be noted, which is beyond the capacity of even our largest super-computers. People who become blind later in life have built up a ‘visual memory’ of the way things look and how they fit together in space. However, for the newly sighted, it is a huge learning task involving a radical change in both neurological and psychological functioning, a change in ‘the perceptual habits and strategies of a lifetime’—in short, in identity.

Sacks says that these sorts of difficulties ‘are almost universal among the early blinded restored to sight,’ and he mentions a patient, S.B., who could not recognize individual faces a year after his eye operation, despite his then having perfectly normal elementary vision.3

From such case histories, it appears that when sight is suddenly restored, there is the need for the development of some new pathways in the visual cortex of the brain. Thus the story of the Bethsaida blind man who saw ‘people as trees walking’ is not a poetic account; it is a clinical description. Like Virgil, this blind man could see, but he had the additional complication of agnosia—he could not make sense of what he was seeing. Jesus, having given his eyes sight, then heals his agnosia—in one miraculous instant his brain was taught what the rest of us have learned from childhood.

So why did Jesus do it this way for this man, as He didn’t have to, and apparently did not do so for any of the other blind people He healed?4

We don’t know for sure, but perhaps it is because, in healing the Bethsaida man in these two stages, He has given a built-in stamp of authority to the authenticity of the account, one that is discernible only to modern-day readers. There is no way that an apocryphal or fabricated tale could have had these details: surgical correction of congenital blindness was not being done then, so the author could not have known about the problem of agnosia in the newly sighted.

It is thus irrefutable evidence that a miracle did occur at Bethsaida. This miracle of healing would have involved restoring or creating eye structures, as well as creating new nerve pathways and connections in the brain. It was thus of the same order of miracle-working power as the making of Adam from the dust of the earth or Eve from Adam’s rib, in a similarly short time (Genesis 2:7, 21–22).

Why did Jesus heal this way?

This is the only two-part healing of a blind person in Scripture. Why did Jesus do it this way?

Looking at the surrounding context in the Gospel of Mark is instructive. Directly before this account, the disciples misunderstand Jesus’ teaching about the leaven of the Pharisees in Mark 8:14–21. Note especially Jesus says, “Having eyes, do you not see?” The story ends without an indication that the disciples understood Jesus’ point, even after He had explained it.

Immediately after the healing of the blind man, there is Peter’s confession of Christ in Mark 8:27–30. So surrounding this miracle, we have the disciples going from a partial to a full understanding of the identity of Christ, just as the blind man went from partial to full sight. We know that Jesus’ miracles had a theological motivation, and so it is probable that Jesus had this in mind when He healed in this way. It’s also likely that Peter (Mark’s source, according to reliable church tradition) interpreted it this way, which showed in the way Mark arranged his Gospel.

Published: 18 May 2011

References and notes

  1. Sacks, O., An Anthropologist on Mars, Knoff, A.A., New York, pp. 108–152, 1995. This true story was made into a film At First Sight, released in 1999, starring Val Kilmer as Virgil. Return to text.
  2. 20/100 vision means that the person sees details at 20 metres that a person with good eyesight (20/20) can see at 100 metres. Return to text.
  3. Case history: Gregory R. and Wallace, J., Quarterly Journal of Psychology, 1963. Return to text.
  4. There were no miracles involving restoration of sight in the Old Testament. It is presented in the Bible as the special activity of the Messiah (Isaiah 35:5; Luke 4:18; John 9:32–33, 38), and was the most frequent of Jesus’ miracles. Return to text.