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The 'Mystery' of Believing Without a Causal Story

Why do we sometimes believe things that we don't fully understand?

Key points

  • Many people maintain beliefs in religion or science without understanding the how or why of their efficacy.
  • People appeal to religion for some needs and to science for others.
  • The lack of an observable cause-and-effect process does not seem to deter believers.
  • Some practices based on beliefs that are unsubstantiated (It's a mystery!) nevertheless serve their purpose.

For all of her adult life, my grandmother woke up around 4:00 a.m. every single day for her morning prayer. She had a stroke in the last days of her life, and some things had changed with how she talked, moved, and laughed, but nothing had changed about her trust in the power of prayer.

A few months ago, a friend of mine who was experiencing unbearable cramps during a very difficult pregnancy told me that the severe pain subsided after her relatives organized group sessions from miles away and sent her healing energy. Another friend ordered expensive supplements to help a relative cope with the symptoms of schizophrenia.

Across the world, many believe that prayer is an effective strategy to bring about short- and long-term outcomes, that distance reiki heals the body, or that vitamin B is effective in reducing symptoms of schizophrenia. But how does prayer, reiki, or vitamin B work in these cases? What is the mechanism or the cause-and-effect story that brings about the final desired outcome? In the case of prayer and reiki, perhaps the most straightforward answer is that the how and the why are a mystery. In the case of vitamin B, if not a mystery, it is at least not known how it works. In fact, in a series of studies with U.S. adults, Tania Lombrozo and I show that people do not know how and why things like prayer, creation, the big bang, or evolution actually work, even when they report believing in these processes. My grandmother never really knew how prayer secured her a healthy and happy life, my friend did not know how reiki reduced her pain, and my other friend did not know how vitamin B helped her relative manage symptoms of schizophrenia. Yet, all three had no doubt that these things do work.

From a purely rational perspective, it may be surprising to find out that the knowledge gap when it comes to understanding how and why some things work has no bearing on our belief that these things do work. However, in a paper published in the Journal of Experimental Psychology: General, Tania Lombrozo and I argue for a model of religious and scientific cognition, which helps explain these patterns. In three studies, we ask how the roles that science and religion play in our lives may be different. The results from these studies support what we call “functional differentiation” between the roles of science and religion. The phrase “functional differentiation” describes the finding that while adult participants in the U.S. are more likely to appeal to science for the need to understand cause-and-effect relations, among other epistemic needs, they appeal more often to religion for other kinds of needs, such as the wish to belong to a community, find meaning in life, or relief from anxiety. But how does this explain the surprising observation that gaps in knowledge about the how and the why of a belief do not weaken the belief itself?

Let us focus only on supernatural/religious beliefs for now. If the main function of these beliefs is not necessarily to paint a precise causal picture of the world, but rather to instill life with meaning and tranquility, then why should a mechanistic understanding of supernatural beliefs, like the power of reiki, or religious beliefs, like the power of prayer, matter at all? The belief that distance reiki works to reduce unbearable pain likely provides emotional comfort for my friend who cannot otherwise do much about her cramps. The belief, then, is serving its purpose very well, despite a lack of any insight into the causal story that explains how reiki works. In fact, there may be no additional benefit to seeking to understand the cause-and-effect story. Chances are the belief in the efficacy of reiki serves its purpose precisely because it is unknown how and why it works.

But what about scientific or pseudo-scientific beliefs? I hinted earlier that, based on evidence from empirical studies, we know that people expect scientific explanations to accurately present the causal structure of the world. This suggests that for a scientific belief to serve its purpose well, it should provide insight into how or why things work. But this conflicts with the observation I made about my friend who believes that vitamin B helps her relative manage the symptoms of schizophrenia, although she does not know how or why this happens.

In recent work, Tania Lombrozo and I presented U.S. adults with an experimental paradigm that, for each participant, identified scientific and religious beliefs that they confidently held (let’s denote the content of the belief with x), but did not know the how and why of x. For example, some participants reported confidently believing that humans evolved from earlier forms of primates but that they do not know how and why this happened. We then asked participants what the most appropriate answer would be to the question of how and why. We presented them with the following four choices: "It’s unknown to me"; "It’s unknown"; "It’s a mystery to me"; and "It’s a mystery." We found that the most commonly selected choice for scientific beliefs was “it’s unknown to me” (and for religious beliefs, it was “It’s a mystery”). This suggests that in the case of scientific beliefs, or at least those beliefs that we think are scientific, even if we do not know the how and why, we suppose that someone else, perhaps an expert, does. Thus, the knowledge gap in these cases is not an absolute gap, but a reflection of the limits of our personal knowledge. In light of this, it makes sense that not knowing the how and why of x, where x is a scientific belief (or pseudo-scientific belief), would not weaken the belief itself. I still don’t really know how the COVID-19 vaccine that I got works, but I hold the belief that it does, mainly because I trust that there are experts out there who do know exactly how it works.

Relatedly, in another study, for each participant, we again identified the same kinds of beliefs (x). We first asked participants to rate their confidence in the belief, and then asked them to imagine a trusted expert in the relevant domain who affirms that the how and why of x is “unknown” or “a mystery.” Then, we asked participants to rate their confidence in the same belief again. In the case of scientific beliefs (e.g., the belief that CO2 emissions contribute to climate change), we found that participants’ confidence drops when they imagine that an expert also doesn’t have the answer to how and why (e.g., how and why CO2 emissions contribute to climate change). Presumably then, if I could prove to my friend that no trusted expert has the answer to how and why vitamin B helps manage symptoms of schizophrenia, her confidence in the belief would decrease, unless of course other reasons for holding the belief are at play; for example, my friend might be emotionally invested in the idea that vitamin B works in managing schizophrenia,1 in which case it might take more to convince her otherwise.

Over the course of history, when people have wondered about the how and why of a phenomenon, they have started to investigate it, a process that in a lot of cases has resulted in scientific advances, and eventually, in revised beliefs. Yet, not all phenomena seem to be the amenable to investigative questions. From my grandmother’s perspective, her early morning prayers seemed to have served an important purpose. Yet, I’m certain she never once thought about the steps or causal story involved going from the words that she whispered during namaz all the way to the positive outcomes she experienced in life. I even think that if someone had asked her about the causal story, she would have said that it’s irrelevant or maybe just that it’s a “mystery.” In fact, a lot of beliefs might have served their purpose and persisted within and across generations and cultures precisely because we are inclined to stay away from questions about how and why.

1 Researchers sometimes call these other types of reasons “motivational reasoning.”


Davoodi, T., & Lombrozo, T. (2021). Explaining the existential: Scientific and religious explanations play different functional roles. Journal of Experimental Psychology: General.