Validity of science
John Martin (Letters, 13/11) is correct. Dark matter is not an established fact. It is an assumption. Scientists seek validity by employing a working hypothesis. Beliefs are tested to find supporting evidence, and conclusions that fail the test are discarded.
Scientists seek validity. Religion assumes validity in unconditional beliefs. However, Martin’s examples are irrelevant to the reason many are abandoning religion. Priests told me hell was in the centre of the Earth. Geologists showed this wasn’t true. Earth was the centre of the universe; Galileo showed that was wrong; the universe comprised our galaxy only. Now we know there are billions. The universe was stable as God made it — another error; nebulas are constantly creating new stars as the universe expands. All are scientific facts. Roy Gilbert, Perth, WA