A while back, I wrote a guest post on Bruce Gerencser's blog The Way Forward in which I discussed what science is. Some interesting conversations and comments developed on that post (they are visible at the end of the guest post), which got me thinking a bit more about a common misunderstanding about science and its role in uncovering knowledge. I appreciate the comments others have made and the discussions that have ensued. I want to make it clear that I'm not out to win an argument with anyone about this topic, but as a scientist I do often see people misunderstanding science, and there is a deliberate battle against science going on in society at the moment because scientific advancement always challenges the agenda of those who are dogmatic, superstitious or bound to belief in a single book such as the Bible (in many ways this has always been the case - think Galileo).
So, the common misconception is a function of interpretation of the fact that science has not yet given us all knowledge. Science is a process of discovery, it leads to knowledge. Science is capable of leading to knowledge about all things that are knowable, though it does not always do this for two reasons: 1) sometimes the resources (money and technology) are not available to run the experiments; and 2) some things are inherently unknowable - some questions simply have no answer.
In either of these cases, but more commonly in the first case, many non-scientists are tempted to state this as a limitation of science, that science cannot provide all knowledge. Since there are gaps in knowledge, some people believe that those gaps represent things that science cannot tell us, and which other non-scientific methods of discovery can tell us. Often, these types of things that are claimed as outside the realm of science are spiritual or supernatural. While it is technically correct to state that science cannot uncover knowledge of the supernatural, that is only because there is no evidence of the supernatural. To this point, we would be wrong to assume that the supernatural exists, because there has never been any evidence to support it. But, to then claim that that is a shortcoming of science is a fundamental error. Science is not limited because it cannot explain the supernatural. The supernatural does not exist, therefore there is no knowledge of it to uncover. How do we know that the supernatural doesn't exist? Because there is no evidence for it, and there is evidence for everything that exists.
Along the same lines, it is often erroneously claimed that science cannot disprove the existence of God. This is a very common claim, and one which people make when they have some rudimentary understanding of how science works. Once you understand that science examines evidence and then draws conclusions, you are able to look at things for which there is no evidence and claim that science cannot disprove it. An example would be the claim that science cannot disprove the existence of an invisible deity. But that is very different than claiming that science cannot disprove the existence of a specific god, such as the Christian God. By extending that claim to a specific deity, the claim no longer holds true. The claims about the Christian God are well known and are described in detail in the Bible. All science has to do to disprove that particular god is to disprove some of the things that are claimed about him. For example, once science showed that the world didn't come into existence in six days, there was a massive piece of evidence against the Christian God. (Christians might then start to claim that the six days are only figurative, that they might represent a much longer period of time. But notice that this claim was only made after science had shown that the world was not made in six days, as a form of trying to make the old conclusion fit the new evidence). I attempt to tackle this issue in a previous post entitled "God is Indeed Dead: It is Scientifically Provable."