ALED Jones (Seeing the light, Letters, November 8) talks about tales of a bright light in near-death experiences.

Our retinas convert light energy into neural signals which are sent to the visual cortex at the rear of the brain.

Apparently the visual cortex is usually stable but can become over-stimulated when deprived of oxygen and near-death experiences can produce the illusion of going down a tunnel towards a bright light.

Prompted by religious stories force-fed from childhood, we imagine these experiences as proof of walking toward God or Heaven.

Even scientists use the term God to fill the gaps in their knowledge. Physicists are accelerating particles and smashing them into one another creating sub-atomic particles.

They are searching for what they call the God particle, because without it, the 16 observed particles that formulate the standard model of the Universe would not have any mass, so there must be another particle that adds mass.

Should the God particle be found, they still have to balance the macro world with the sub-atomic micro world of quantum mechanics, including the uncertainty principle.

They have infinite time in a universe expanding into infinity to solve the puzzle. As long as the human race can become infinite.

Sir Isaac Newton said: "To myself I am but a small child wandering upon the vast shores of knowledge, every now and then finding a small bright pebble to content myself with while the vast ocean of undiscovered truth lay before me."

As science inches forward the human species will make great advances and many of the worries of today will be no more. We should concern ourselves with improving the lives of everyone alive today. Politicians take note.

T Scaife, Manor Drive, York.