In chemistry or physics you can always go back to the beginning and repeat an experiment to  see if it gives a consistent result. The origin of  life and the formation of the variety of species that fill the globe was different. It was a one-off, a unique event long before our time. And so far as is known, no other planet or star in the vast universe has living things like ours. So evolution can only ever be a theory, a possible explanation for the finished result. We have to decide for ourselves whether it is reasonable; whether it fits the facts.

Unfortunately, there are a number of flaws in the theory. Some of them are so damning, that if we  were lawyers at a criminal trial, we should protest  that the conviction of our client was unsafe. We  have already hinted at one of these difficulties, and  it is time to develop the point more fully. It has to do with the very long time span the evolutionist claims for the development and refining of the special  features that distinguish one species from another.

Everyday experience teaches us that like begets like. As Jesus once said, you do not gather figs  from thorns, or pick grapes from a bramble bush. All living things have only a limited scope for  change from one generation to another, because reproduction works with extraordinary genetical  precision. In fact, the biologist would insist that the only possibility for a fundamental change  to take place between one generation and other, is when the process of reproduction goes wrong.  There has to be some form of damage, a chemical change in the sequence of codes, which arises by  accident, and which survives being divided and reassembled during cell division. Only then can a  change be passed on into succeeding generations. These changes, called mutations, are random and  unpredictable.

Most known mutations that have survived are harmful rather than beneficial. In humans, the notorious ones cause unpleasant defects such as colour blindness and haemophilia (persistent bleeding). The evolutionist, however, claims that some mutations, occasional ones here and there, are actually beneficial, and result in an animal or plant better  fitted to its environment. Since the mechanism of reproduction is geared to preventing accidental errors, the scope for change in species like humans who have a long interval between generations is extremely limited. It is for this reason that the evolutionist needs to rely on long time scales to allow  time for development to take place, frequently of the order of millions of years.

Although at first glance extending the time  period for development appears to make evolution  more plausible, this is not always the case. In fact, for  some aspects of the natural world a long timescale would be a positive hindrance.

The human eye, for example, is a superb instrument.  It has auto focus, instant adjustment of the  aperture, full colour perception, and a range of sensitivity to light beyond the most expensive camera. Yet it functions continuously for eighteen hours a  day over more than seventy years, with only gradual  deterioration in efficiency. But we shall leave on one  side how such a fantastic camera could come into  being through nothing but natural selection, and we  shall not enquire about the problems of a partially  developed eye. Concentrate instead on human tears.

We are unaware of our tears, most of the time.  Only when we are upset and they begin to overflow  do they become a nuisance. Most of the time the salty, antiseptic secretion of the tear glands carries out its vital role of lubricating and cleaning the  delicate but exposed surface of the eye, the cornea,  with impressive efficiency.

But what happens to our tears when we are not  crying? Why don’t they run down our cheeks all  the time, getting in the way? The answer is that in  the inner corners of the eyes are two tiny tubes,  about one centimetre long, the tear canals, which  drain away the surplus liquid. You can see the entrance  to the lower one as a small pinhole in the rim of the eyelid. The canal drains the tears into a  collecting sac, and discharges the moisture via a  long channel in the bone of the skull to an exit hole  on the inside of the nose. That is why the bride’s  mother always blows her nose at the wedding! As the tears well up in her eyes, the tear ducts bear them away into the nose. Sometimes you can taste the salt, if you sniff when you have been crying.

19-6 eyes

Now the question is, how did these tiny tubes  evolve? How would a tear canal begin? Did a  depression arise on the inside of the eyelid of an  early mammal, and then generations later a tube  begin to extend away from this depression? Bear  in mind that an incomplete tube would serve no  useful purpose, and should theoretically have been  eliminated at once by natural selection. Assume that  it survives, and after a few hundred thousand years  it begins to meander down through the thickness of the eyelid.

We now have to imagine a channel opening up  for it through the bony ridges surrounding the top of the nose. If there was no way through, the embryonic  tube would reach a dead end as it struck the  bone, like an oil rig drill meeting impenetrable rock.  Even if there was a channel already there, it would  be pure coincidence if the tube developed towards it.  Subject purely to random mutations, it has no reason  to aim downwards and inwards. In fact, we might  have to consider that there were first of all dozens  of tiny tubes springing up in different parts of the  eyelid in turn, some near the outer corner, some in the middle, until at last, after millions of years, one  tube on the inner corner coincided with a channel  that had independently developed in the bone, and  broken through the inner lining of the nasal cavity,  somehow forming a neat, unblocked exit hole.

Now, at last, the tear duct would be able to  serve a useful purpose. Fluid could finally flow  from the eyeball to the nose and throat. Through all  those long millennia, early mammals would have  blundered along, their vision blurred by the tears their eyes must have to keep them clean, and their cheeks permanently wet with an irritating overspill.  You see how problematical the theory of evolution is when you apply it to a practical example. A child would immediately declare that there is only one explanation for the tear duct—an Intelligent  Designer, who, having perfected a remarkably sophisticated living camera with a built-in lubricating  and cleansing system, saw the need for a drain, and put one in, to discharge excess fluid tidily into the nose.

Observe too, that extending the timescale to  increase the probability only makes things worse.  Right up to the point of final breakthrough, the tear duct would serve no useful purpose, and  man would still be condemned to a fuzzy view of  his world. “Understand, you senseless among the  people; and you fools, when will you be wise? He  who planted the ear, shall He not hear? He who  formed the eye, shall He not see?” (Psalm 94:8,9).