Science has taught us that the light is reflected from any object in this universe that we observe, and travels to the retina in our eye. There are 120 millions rods which are sensitive to black and white and there are about 7 millions cones which are sensitive to color. These rod and cones convert the incoming light into an optical signal. This optical signal is transmitted to the visual cortex in the human brain. This is the end of the journey of the perception process. There is no explanation as to what happens to the optical signal and how the brain decodes the optical signal and reconstructs our visual world. Science also never tells who is at home within the brain who finally sees the reconstructed visual image. Who is final observer of this image? I guess this idea of the final observer has always been outside the bounds of science because there is no way to empirically record the observer’s existence. Anything “subjective” is discarded in the scientific world.

Besides the lack of understanding of the observer and what happens in the mind/brain in the reconstruction of the outside world, there is this unanswered question – does the incoming light reflected from objects have the capacity to generate the awareness of those objects? It would seem this reflected light is our only connection with the outside word. We are aware of all the objects both far and near only because of this reflected light. I think this asking too much from reflected light (photons) alone. Here are some reasons:

1. If you look at a far away star, the light traveling from there can take a long time. For Star A which is 10 light years away, the photon has to start traveling 10 years back so that it can hit the retina in our eye now to make Star A visible. Now we turn around and try and see Star B, which is 1 million light years away, that photon would need to start its journey 1 million years back so it is available to our eyes. This is a long journey for the photon passing through space containing dark matter, galaxies, and planets. The photon has to keep its purity of wavelength and energy level. Now if you can imagine millions of people spread over many different galaxies looking at the same stars at the same time, different photons from Star A and B should also travel from the past to the present to reach these millions of viewers. It would seem these photons from anywhere in the universe are available to viewers everywhere on demand and that too instantaneously. This makes you wonder- is there is a limit on the number of photons the reflected light can generate from the object which has to be viewed?
2. We know light is made up of different colors and each of the colors has a different wavelength. When we pass light with these colors through a prism (basically from one medium to another), the wavelengths for each color bend differently and we see the rainbow effect on the other side of the prism. Light breaks up and moves in scattered directions. It is more than likely the light coming from distant objects will pass through different media which only means the photons of different colors will scatter and move in different directions. The probability of scattering is much higher if the light has to travel from stars which are light years away. If this is really happening what is the accuracy of the photons reaching the human eye? Is it really representing the objects accurately? I do not think science really discusses this and it is taken for granted that the photons reaching us from distant objects are an accurate representation.
3. Another critical question is – how can the photon accurately represent the distance and time it has travelled? The object could be close by or a distant star. Quantum physics tells us these particles are continuously destroyed to become other particles and then they combine once again to become a photon. Such a dance is going on continuously. Keeping this dance in mind, there is no way to know which photon has traveled how far to reach the human eye. As of now there is no indication that the photon has some sort of memory to know from which object it has come and the distance it has travelled. There are millions of photons hitting the rods and cones in the retina, but there is no way to know which photon comes from which object and how much distance it has traveled. If this critical information is lacking, it is impossible for the eye to reproduce the image we are trying to perceive.
4. You could say that this is perhaps unknown to science – the photon does have memory to know the distance it has travelled. If so, how does it transfer this distance data to the retina? The retina in turn must add the data regarding distance into the optical signal being sent to the brain. Only this way, the brain can reconstruct the visual image accurately.

Science is completely silent about this and there is no evidence that all this is actually happening. All the above arguments show it’s just not very clear how we really perceive. What science tells us so far is full of problems and shortcomings.

For all the reasons mentions, I think photons are overrated for its importance to the perception process.

Read the article ‘Real Perception Process’  to undertand how the actual percption process works. This is based on the teaching of Vedanta.