The term will probably not work its way into your casual conversation any time soon. However, it may play a part next time someone talks to you about your faith. It should play a part next time you talk to someone about yours.
Plausibility structures are what they sound like—structures in our thinking that determine which ideas are plausible enough for us to believe. Albert Mohler describes the more personal aspect of the term as “certain frameworks of thought that are necessary for our understanding of the world.” Lesslie Newbigin explains the concept on a broader level:
…patterns of belief and practice accepted within a given society, which determine which beliefs are plausible to its members and which are not….Thus when…a belief is held to be “reasonable,” this is a judgement made on the basis of the reigning plausibility structure.”
Translation: Plausibility structures are ideas that we take for granted on both a personal and societal level, but they determine what we are likely to believe or not believe.
When we are confronted by an idea, whether we accept it as true will be largely determined by whether it fits within the framework that our plausibility structure provides for us.
I have seen a great example of how plausibility structures work in my ten or so years of teaching high school history. The first time I taught about ancient Egyptian pyramids, I pointed out how they have perplexed archaeologist and engineers for ages. I explained that modern minds have hardly figured out how they were built given the technology of that age. In passing, I mentioned that some even suggest that aliens helped with the project. The first couple of years in my career, the students laughed, and we moved on. That was that.
Apparently, extraterrestrial engineers simply did not fit within their plausibility structures.
Then, the “History” Channel (imagine the most sarcastic finger quotes possible) launched the show, Ancient Aliens. Additionally, entire movie and TV franchises have been built on the notion of extraterrestrial panspermia, the idea that aliens seeded all life on Earth. I noticed that as time went on, when it came time for my classic Egyptian alien jokes, the laughs were noticeably fewer and farther between. Currently, when I broach the topic, I get more brooding glares than laughs.
Apparently, extraterrestrial engineers increasingly fit within their plausibility structures.
Author Joe Carter illustrates well when he refers to plausibility structures as “a belief-forming apparatus that acts as a gatekeeper, letting in evidence that is matched against what we already consider to be possible.” This gatekeeper allows into our beliefs only those ideas that match what we already assume. Furthermore, it keeps out any idea that challenges what we assume is possible.
This is why we often seem so resolute and unmovable in our opinions. It applies to everything from political allegiance to cultural tastes. Any time we encounter an idea that challenges our thinking, our plausibility structures either interpret that idea as supporting “our side” or dismiss it altogether.
The bottom line is that plausibility structures do not tell us if an idea is true; they tell us if an idea is believable. They take what we already assume about the world and create a filtration process for our thinking. They keep the gate of our beliefs, only letting in those things that will not disrupt our current belief system.
Plausibility structures are helpful for us to understand for at least two reasons.
1. To better understand why culture moves the way it does
Cultural commentators argue about whether or not we can officially call the U.S. “post-Christian America.” Some see all signs pointing to a rising tide of secularism. Some claim that we are much more religious than many assume. Regardless, two things are obvious to us all.
First, traditional Christian beliefs are no longer plausible in most public conversations.
This is especially true concerning sexual ethics. A Biblical understanding of sexuality was at one point the reigning plausibility structure on the issue. With the cultural changes of the mid-twentieth century, Biblical morality was seen as backward or old-fashioned. Today, it is viewed as inferior and even hateful.
Pastor Steve McAlpine explains how this has happened in Australia:
When it comes to sexual ethics now, it is not simply that traditional Christianity has “strange” or “weird” or even “interesting” perspectives, but rather “wrong”, “bad”, “unenlightened”, even “sinful” positions. Read the opinion pages. …For decades in Australia Christians were regarded pejoratively as “do-gooders”. In Second Stage Exile the pejorative is “do-badders”.
Because plausibility structures regarding sexuality have changed so drastically in the past half-century, Christian ideas about the topic are filtered out on a societal level as downright implausible.
Second, traditional Christian beliefs are no longer plausible in many private experiences.
As Christian thinking lost dominance in the public square in favor of secularism, Christian thinking lost preeminence in the private marketplace of ideas to the same alternative. There was a day when atheism was simply unthinkable. Today, for many people, Christianity is simply unbelievable.
We cannot say that atheism or agnosticism dominates private thinking. It is not that simple. Just over 7% of the U.S. population identifies as atheist or agnostic. However, that number is double of what it was less than a decade before.
By all accounts, the fastest growing religious category in the U.S. is the religiously unaffiliated, known by the nickname nones. Curiously, while 49% of nones claim flat unbelief, the remaining slight majority claim some religious belief. Nevertheless, those beliefs are framed by a strong aversion to organized religion, an undecided spirituality, or religious inactivity. In other words, for a growing number of U.S. citizens, robust religious belief is becoming less and less plausible.
Our society has built secular plausibility structures, and our culture has responded accordingly. From government to entertainment, virtually every cultural institution moves forward with a deeply rooted assumption that either God does not exist, or if he does, he is largely irrelevant in our day-to-day lives. Thinking otherwise is simply implausible.
2. To better understand why people believe the way they do
Talking to my students, I often feel like we are speaking different languages. They often report feeling the same way. Oh, we understand what we are saying to each other. We just have no clue what we mean with what we are saying.
While I am fairly certain this is not a new phenomenon in communicating with teenagers, I notice it happening more and more in speaking with other adults as well. We may use the same terminology, but it cannot be assumed that we mean the same thing. This is because we are probably working with different plausibility structures.
For instance, if I am speaking with Hindu neighbors, my belief in a single sovereign God may not have much sway for them. That is because Hinduism worships 33 million gods that function more like spiritual bureaucracy. On the other hand, if I am speaking with Muslim neighbors, my belief in the deity of Christ may have an aversive effect. This is because the idea is regarded as shirk, the sin of idolatry or polytheism, and flies in the face of the strict Tawhid monotheism.
Similarly, I may meet a person who believes that science is the only reliable source of knowledge, and anything outside the realm of science is ultimately unknowable. To them, my Christianity with all its talk of miracles and the supernatural will seem outdated and far-fetched. Moreover, I may meet a person who has been mistreated by religious people who were protected by religious organizations. To them, my Christianity will be implicated in their horrific experiences.
Plausibility structures shape the way people think about new ideas based on the way they think about old ideas. Therefore, when we as Christians present Christian ideas to non-Christians, they will judge those ideas based on whether or not it is within the framework of what is believable in their mind. Our job, by way of evangelistic apologetics, Biblical theology, and Christ-like living is to convince them that if Christian belief does not fit within their plausibility structures, then there is a need for expansion.
So here’s the thing…
Understanding plausibility structures cause us Christians to remember at least two things:
First, it is important for us to remember that when we speak to people we are not speaking to blank slates any more than they are when they speak to us.
Second, it is important for us to remember the life people see us live has a profound effect on how plausible our faith is in their minds.
 Al Mohler, “Darkness At Noon: The Closing of the Postmodern Mind” (https://albertmohler.com/2005/12/07/darkness-at-noon-the-closing-of-the-postmodern-mind/)
 Lesslie Newbigin, The Gospel in a Pluralist Society (Eerdmans, 1989), p. 8.
 Joe Carter, “Apologetics and the Role of Plausibility Structures” (https://www.thegospelcoalition.org/article/apologetics-and-the-role-of-plausibility-structures/)
 Steve McAlpine, “Stage Two Exile: Are you ready for it?” https://au.thegospelcoalition.org/article/stage-two-exile-are-you-ready-for-it/
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