A couple of years ago, some friends and I had a discussion on the merits of accepting something as true based on subjective experience. As an example of what I mean by subjective experience, imagine saying a prayer and then observing a rainbow. There are those who have had such an experience and concluded that this was a sign from God. When such an experience leads to the conviction that the Christian God exists, I would call this a "truth" that is believed on the basis of a subjective experience. I am pretty certain that the rainbow formed independent of the prayer. But how can I know?
There are many examples of things that people accept based on subjective experience that can be shown false based on objective evidence derived through the scientific method. For instance, certain Christians were convinced that a weeping Mary painting was a miracle (subjective). An analysis of the tears found them to be made of olive oil (objective); and later, a hidden camera caught the perpetrators pouring olive oil on the painting (objective). This evidence of tampering did not dissuade the faithful from following their hearts and believing that the tears were still a miracle. Given the strength of the evidence, the tears were clearly not a miracle.
Similarly, many people believe that prayers are answered (subjective). An experiment was designed by true believers to test their conviction, which included members of prestigious institutions such as Harvard, and found that there was no connection between prayer and outcome as they had believed. Though objective evidence falsified the hypothesis, many members of the religious research team said their faith in God was strengthened by the results. I find this conclusion totally illogical and an example of how religious thinking leads to false belief.
I define religious thinking more broadly as the process in which conclusions are accepted as true based solely on subjective evidence; which, by the way, is not limited to faith and religion. This is in no way meant to be disrespectful to those who are religions. Rather, the term is apropos on the basis that such thinking is common amongst the religious. Indeed, many religions demand that people accept dogma on faith. To many members of the clergy, the thought of asking for objective proof is near blasphemy.
There are many examples of religious thinking that are found to lead to false conclusions when compared against objectively-derived evidence, and I will not provide an exhaustive list. Those who are interested in this topic can read the Skeptical Inquirer, an excellent publication filled with many interesting articles. My point is that subjective experience is shown over and over again to be a faulty method for determining the truth. If this is so, how can one justify the use of subjective experience as a source of true information?
One may argue that religious thinking is harmless. Often, such thinking is deadly.
Consider the hysteria over vaccinations and a purported link to autism. Many parents are convinced that their children got autism as a result of a vaccination because the onset of symptoms started soon after the inoculation. This correlation does not prove causation. The observation can be explained by the simple fact that the typical age of a child with the onset of autism symptoms happens to coincide with the recommended age for inoculations. Thus, it is no wonder that many children show symptoms of autism shortly after a vaccination.
Studies by a British Scientist that reported a connection between vaccinations and autism was later found to be fraudulent, not to mention inconsistent with the body of scientific evidence. Even with objective evidence to the contrary, many parents are convinced that inoculations are dangerous and have decided not to inoculate their children.
Because of decreased vaccination rates, childhood diseases such as Pertussis (Whooping Cough) are on the rise. In 2010, 10 infants died during an outbreak in California, where about 10,000 cases were reported (see the CDC website). As fewer children become inoculated, the number of cases and deaths will skyrocket. Yet 48 out of the 50 states in the U.S. allow parents to choose not to inoculate their children based on religious or philosophical grounds. The government is allowing religious thinking to trump scientifically established truth.
To protect the public health, it is crucial that nearly 100% of the population be inoculated. When religion affects the welfare of others, it should not be used as an excuse for an exemption.
Emotions complicate matters. It is difficult to watch dejected parents with autistic children carrying banners and protesting against the "evil" drug companies that make vaccinations that "hurt our children" (subjective). The scientific argument is seen as a corporate coverup, and legislation as a sign of government corruption (subjective). Even so, reason must triumph. The scientific method is specifically designed to remove subjective bias, especially when emotions cloud good judgment.
As I wrote in a previous post, this may brand me as an arrogant scientist. However, there are certain things that science knows with great certainty. In such cases, we must enact intelligent policy that protects the public. In short, strong objective evidence must always trump the subjective.
That is not to say that all subjective experiences should be dismissed.
When choosing a spouse, believing in God, or marveling at the greatness of one's own children, we should all be free to indulge our fancies. However, religious thinking must be resoundingly rejected when imposed on others, especially when it contradicts well-established objective knowledge.