VALPARAISO | The Darwinian theory of evolution, because it has not been disproved by rigorous testing over time, has become accepted knowledge, and disbelieving it is not an option.

That was the conclusion of Murray Peshkin, a physicist with Argonne National Laboratory, in a recent talk on science and religion at Valparaiso University.

Opponents of teaching Darwinian evolution have lost the court fight to keep it out of the public schools, Peshkin said, so they have changed the battle to push for equal billing for creationism, or intelligent design.

"What's wrong is teaching those as part of science -- they are not. They belong to religion because their assumptions and their logic belong to religion," he said.

Dismissing science with "it's only a theory," Peshkin said, is "intellectually appalling" and a material threat to the country. Science in the 21st century offers chances to conquer diseases and achieve other advances, opportunities that could be lost if students aren't taught the best science and if parents aren't taught respect for science, he said.

Scientists have failed to explain the limits of science, Peshkin said. Science deals in what can be observed and measured through experimentation. Assertions or beliefs are not part of it. A theory, he said, is a hunch about how the world works that is then subjected to experimental observation.

Religion, on the other hand, accepts revealed knowledge. The two, therefore, take different approaches to reality, Peshkin said.

But each is valid and the conflict between the two is unnecessary, he said.

Peshkin said experimentation can only disprove a theory, but never finally prove it.

With proof always impossible, then, scientists rely on the repeated successful testing of a theory to make conclusions about the physical world, he said. Newton's laws of mechanics are accepted because they have accurately described observable phenomena consistently over centuries. They have been found to apply not only to planets, as Newton started with, but also to baseballs and jet engines. An airplane designed to fly under a different theory of motion would not get any riders, Peshkin said.

Disbelieving well-tested theories is not an option intellectually or practically, he said.

Since the 1900s, Darwin's prediction of primates' descent from a common ancestor through natural selection has been confirmed by repeated observation. The theory of evolution has been subjected to numerous and varied tests and has not yet encountered limitations, he said.