This is something I posted on Facebook about this subject a few years ago:
Scepticism is one of the most important disciplines in science. It is also one of the most misunderstood, especially in Christian circles.
It is important to realise that there is a difference between scepticism and unbelief. The word “scepticism” means something very different in science from what it means in theology. Unbelief is generally based on reasoning that is not well defined—cultural or political views, emotionalism, knee-jerk reactions, or even just good old fashioned prejudice.
It is also important to realise that scepticism is not an open invitation to accept any old narrative or conspiracy theory just because it is “contrary to accepted dogma.” Even if scientists are wrong about something, you don’t get any points for replacing it with something even more wrong.
No, scientific scepticism is simply an insistence on honesty, factual accuracy, technical rigour, and quality control.
Like everything else in science, scepticism is a very methodical and systematic discipline that operates according to well-defined rules. Claims must be backed up by evidence, which must be interpreted in ways that are mathematically coherent and consistent. Results must be reproducible. Cognitive biases must be accounted for. Conflicts of interest must be opposed. Sources must be cited, and cited accurately. Quote mining is completely unacceptable. And so on.
Scientific scepticism may seem threatening to some people, especially if they are not used to having their claims or teaching scrutinised. But it is a thoroughly Biblical concept. The Bible tells us that we are to test everything (1 Thessalonians 5:21); that we are not to believe every spirit (1 John 4:1); and that every matter must be established on the testimony of two or three witnesses (Deuteronomy 19:15; Matthew 18:16; 2 Corinthians 13:1; 1 Timothy 5:19). It is also very, very necessary. Without it, we would be granting a free pass to astrology, homeopathy, water divining, reading tea leaves, feng shui, the Maharishi Yogi, and tobacco companies trying to convince us that smoking is good for you.