In the Story of God on BBC1 last night, Robert Winston argued that certainty in science and certainty in religion are both equally dangerous. I would disagree.
For me, what highlights the difference between the certainty of religion and the certainty of science was demonstrated in the debates that Winston had first with Richard Dawkins and then with a US creationist.
Both Dawkins and Winston, as scientists, laud the need for doubt. Even extreme anti-theists like Dawkins would ultimately admit that there is a possibility of there being a God, but the idea is so ludicrous as to be discounted.
Whereas a creationist and most religious people cannot countenance doubt (indeed they see it as a weakness in their faith). This is the first important difference.
The second difference was highlighted in the debate between Winston and the creationist. Every time Winston admitted that a particular scientific theory was not an absolute cast iron certainty, the creationist jumped up and down claiming victory for his argument for God. Of course the first thing to point out is that the evidence for scientific theories like evolution are overwhelming, whereas the evidence for a God is non-existent.
We can never be certain about the decisions we make in our life and those who follow science accept this, faith is different.
Decisions in life are best made using the widest available evidence that science provides. What makes religious belief dangerous, is this dis-regarding of evidence, using ignorance of science and fear of the unknown as a cover. Of course even those who claim to be deeply religious people are not totally stupid and most wouldn't follow religious teaching where it is obviously detrimental to their life, but religion can have a significant dampening effect on progress (scientific research, gay rights, birth control, etc. etc).
To take religion completely out of this decision making process (but not out of education altogether, religious stories should be taught like Greek mythology) will be a significant victory over ignorance and fear and is frankly long overdue.