For Christians (or anyone else) who deny Darwinian evolution.

[downbeatplumb]

There are a number of reasons why your argument here fails:
A: Something that appears irreducibly complex may not in fact be so.
B: Evolution can discard parts as well as add.
C: Parts can change their usage.



The eye has probably one of the best known evolutionary paths and I know you have been told about this on a number of occasions in the past.

But here we go.

Firstly a brief explanation of the evolution of senses. All senses rely on a similar process, electrical impulses. At the simplest level you can see paramecium use the deformation of its surface to sense hitting something by changing the level of negative and positive electrons internally and this reverses the pulses of its flagella by using waves of electricity, nothing that compares to a nervous system but you have the basis of sensing and reacting. From this you can evolve a brain.

The simplest known proto eye is an eyespot or light  sensing organelle found on algae and other unicelled creatures that senses when its dark or light and can use similar methods to the paramecium to move towards light/away from dark.

From there you can evolve the eye and associated neural functions.

I missed the part where you explain how the eye and the associated neural function developed through successive small changes where both are needed to provide a survival benefit.

Look again because I addressed this at the beginning.

I explained how senses worked then and gave an example along with how those simple sense affected behaviour and assumed you would understand that from that evolution could commence, I then went on in detail to give an explanation of how the eye works.

Further, just recognizing light is not a survival benefit. The organism has to be able to do something about it. So, what function evolved first when all three require the others for any survival benefit?

I gave the an example where elecrical implulses were used to reverse flagellum movement by the changing of the negative and positive electrons so you have the mechanism to change direction now combine that with a sense of light and the paramecium being a photosynthesising creature you get evolutionary pressure that would favour paramecium able to move towards light. You have the ability the senses and the result right there. 

From a light sensing spot if you add a bit of a dip you can sense the direction the light is and that gives more information for the evolving creature to use with its evolving neural system

The deeper the dip, the better the information, until you get a sphere.

Then you can have a number of light sensing spots, people grow extra heads from time to time so adding extra things is a common mutation, adding spots gives the ability to see  shapes.

There are several things wrong with that sentence, but let's stick to the one point. You would need a massive increase in complexity in the processing center to go from the binary light/no light to recognizing shapes and doing something about it that would be a survival benefit.


What survival benefit preserved the increasingly complex (but useless) eye until the organism developed the vastly improved processing center? 

At no stage is the ability useless as mentioned above.

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I am not the one claiming something!! People left and right here claim evolution is a scientific fact.

It is

It is NOT. It is a philosophical claim. This is not a difficult concept. 

Just because you cant understand something does not make it "not science".

I'm not even saying that evolution is a bad theory. It's absolutely the best naturalistic theory we have. To deny there are large gaps of knowledge in how it works and how it played out is just stupid. I for one am waiting until we either fill in the gaps with facts (or better theories) or fail to. My beliefs don't hang on it either way.

Evolution is the best explanation and all the problems you seem to have with it go away after a few moments study.