GEOFFREY Ryland (You Say, December 21) is unable to distinguish between scientific fact and scientific theory.

The distance between Earth and Mars is a fact that can be established and objectively verified.

Evolution and the Big Bang, regardless of whether they are true, are theories. They are speculative conclusions based on evidence and can not be proven, as they happened (if they happened) a long time ago.

Scientific theories are constantly in need of re-evaluation as new and competing evidence appears.

Scientific creationism is an alternative theory to Evolution. It concludes divine intervention in the World's origin on the basis of scientific evidence.

Creationism challenges they theory of Evolution by observing flaws in such as the lack of transitional species in the fossil record and its conflict with the laws of thermodynamics.

Creationism also challenges the idea that the earth is millions of years old by suggesting geological upheavals caused by a global flood as the origin of major geological structures.

MATTHEW A CLARKE,

Worcester.