Evidence-Based Medicine, Evidence-Based Religion

George Washington died in 1799 of an upper respiratory infection, which he most probably would have survived if not for three doctors sending him into hypovolemic shock by draining out half of his blood volume. “Therapeutic” bloodletting was a staple procedure in western medicine at the time, and the practice can be traced back to at least the 5th century BC. Classical Greek medical practitioners, including Hippocrates and his colleagues, reasoned that removing excess blood from the body was a way of balancing the four humors. They even pointed to the female menstrual cycle as a natural example of how the body tries to maintain this balance. This reasoning was more philosophical than scientific, but at the time it seemed reasonable and even plausible. Washington himself was a firm believer in the practice (until it killed him).

Modern people tend to be shocked at the manifest ignorance of bloodletting because we know more about the physiology of the human body than they did back then. At the time this practice became entrenched in western medicine people didn’t understand that blood circulated through the body, and were unaware that arteries connected to veins via capillaries. They thought that blood was produced in various organs and then consumed in others. As medicine gradually began to understand and use the tools of experimental science through the 19th and 20th centuries, and as evidence mounted that bloodletting actually harms patients, the practice was gradually extinguished in western medicine. (Although there are a few rare diseases like hemochromatosis where therapeutic phlebotomy is still employed, and bloodletting is still used in some alternative medicine systems.)

Evidence-Based Medicine

The past 200 years have witnessed an incredible revolution in medical technology. The downfall of therapeutic bloodletting is just one example of how biomedical science has improved the practice of medicine, and I have shared other examples in previous posts: Alternative Medicine and Science and Religion. The goal of using science in medicine is to make medicine better: more effective, more efficient, less harmful, etc.

The most robust application of scientific methodology to medical practice is known as “evidence-based medicine,” a term which was coined in the 1980s. The basic idea is to use the best available experimental evidence to formulate treatment guidelines, which are then used by medical educators to train students and residents, by practicing physicians to stay on top of new developments, and by insurers, government regulators, and other organizations to evaluate (or mandate) the care delivered by hospitals and clinics.

For a practicing doctor, this means that when I am sitting down with a patient to make decisions about what diagnostic tests I am going to order and what treatments I am going to prescribe, these decisions should be made using guidance from the best available evidence about the clinical utility, cost versus benefit, and safety of whatever test or treatment I am considering. Doctors practicing evidence-based medicine don’t have to make up everything as they go, or blindly perpetuate the errors of medical tradition. We don’t have evidence to guide every decision, so we lean upon our experience and our best intuition to plaster over those holes, while we continually incorporate new data in our practice.

Oh, Say, What Is Truth?

The purpose for gathering evidence is to point us towards truth. Implicit in scientific inquiry is the assumption that truth exists, and that it can be discovered and known. Latter-day Saints take a similar view of truth, in both religious and secular contexts. We look to God as the ultimate source of truth, and when truth is made known by any means, we should be willing to accept it and give credit to God. As explained in our 9th Article of Faith:

“We believe all that God has revealed, all that He does now reveal, and we believe that He will yet reveal many great and important things pertaining to the Kingdom of God.”

Just as scientific discovery is a cumulative, iterative process, continually building on and revising the work of past discoveries, God’s revelation is given “precept upon precept; line upon line, line upon line; here a little, and there a little.” God has authority to reveal whatever he wants, whenever it suits his purposes. He can clarify our understanding of previous revelations, and can correct false doctrines and false practices which creep in over time.

Latter-day Saints believe that God revealed religious truths to Joseph Smith, clarifying many doctrinal questions. We consider these new revelations to be scripture, because they were revealed by God to a prophet just like the ancient scriptures were. Did God have authority to give revelations to the Apostle Peter to guide the early Christian church? If so, then he still has the authority to do the same thing today. For Christians who accept the authority of God, the question is not whether God could call a prophet in our day, but whether or not he did. We declare that he did.

Evidence-Based Religion

Faith is not blind, or at least it should not be. Belief is a choice, but we want our choices to be rational. Fortunately, the Christian religion is evidence-based. The Apostle Peter exhorted, “be ready always to give an answer to every man that asketh you a reason of the hope that is in you.” Christians hope for, and long for, salvation through Christ. Peter indicates that this is a rational hope, based on reasoning or evidence of some sort, and that this reasoning can and should be communicated to others.

Believers use various types of evidence in determining their beliefs, and different faith traditions use evidence in different ways. I have lately been following a couple of Christian apologetics blogs, which I find very interesting. Taking their cue from Peter’s exhortation quoted above, Christian apologists through the centuries have outlined and developed multiple lines of argument using philosophy, logic, and history to show how reasonable it is to believe in God, the scriptures, the resurrection, and many other important Christian concepts. Latter-day Saint apologists have taken a similar approach to defending the doctrines and history of the Church. (Probably my favorite example is this fantastic General Conference address by Tad R. Callister about the Book of Mormon.) The goal of these efforts is not to definitively establish the truth of the religion using argument or debate, but to address and  debunk the reasons why some people might not believe. If you take away the causes for unbelief, then maybe belief can start to grow.

sowerIn the parable of the sower, Jesus describes the word of God as being like a seed planted on different kinds of soil, with the different soils representing different conditions within people’s souls. Seeds that landed on hard-packed dirt had no chance to grow, and seeds that landed on stony ground or among weeds were inhibited in their growth. Apologetics can be likened unto the effort to clear away the rocks or weeds from the soil, or to break up the hard-packed dirt with a plow or tiller. These efforts alone will not cause plants to grow in the soil; you still have to plant the seed.

The sort of evidence put forward by apologists is not sufficient to produce faith; it merely provides an antidote for the poison of doubt. Faith is built upon a different kind of evidence, and it takes time and effort to collect it. The process essentially boils down to trying it out for yourself and seeing what happens. For instance, if you want to understand what prayer is all about and why you should do it, then you should try praying consistently for a time. If you want to know whether or not the Book of Mormon is true, then you should read it and pray about it. If you want to know whether paying tithing will really “open the windows of heaven” for you, then pay your tithing and find out for yourself.

We also collect evidence in the form of transcendent, or spiritual, experiences with God. Most of these come through the Holy Ghost, and produce a variety of emotional and cognitive experiences (some of which are described here and here). These experiences can be difficult to describe to others. They come in the Lord’s time, and they cannot be produced upon demand, but they will come to you eventually if you plant the word of God in your heart.


I believe in God, in his Son Jesus Christ, and in the Holy Ghost. I believe that salvation comes through Jesus Christ, and that the Bible is the word of God. I believe that Joseph Smith was a prophet, and that the Book of Mormon is true. I believe that The Church of Jesus Christ of Latter-day Saints is the Lord’s church, restored to the earth in preparation for his second coming.

Why do I believe these things? Because of evidence, collected over many years. Evidence in the form of apologetics tells me that the arguments against belief are unreasonable. Evidence in the form of life experience tells me that living the teachings of Christ produces all of the promised blessings. But the most important evidence to me is the “still small voice” of the Spirit of God, whispering to my soul that what I believe is true.

Alan B. Sanderson, MD is a member of The Church of Jesus Christ of Latter-day Saints and is a practicing neurologist.

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