"Begin at the beginning,” the King said, very gravely, “and go on till you come to the end: then stop.” — Lewis Carroll, Alice in Wonderland
We begin by suggesting a framework of secular belief. It begins with the simple question, How can I justify any of my beliefs?
When thinking about why we believe in anything, we quickly realize that every belief is based on other preexisting beliefs. Consider, for example, the belief that brushing our teeth keeps them healthy. Why do we believe this? Because brushing helps removes plaque buildup that causes teeth to decay.
But why do we believe plaque causes decay? Because our dentists, teachers, and parents told us so. Why do we trust what our dentist says? Because other dentists and articles and books we’ve read confirmed it. Why do we believe those accounts? Because they presented many more pieces of information confirming the link between plaque, bacterial growth, and tooth decay. And why do we believe those pieces of information?
There seems to be no end. It’s like the old story of a learned man giving a public lecture in which he mentions that the earth orbits the sun. At the end of the lecture an elderly lady approaches the lectern and sternly informs him that he is wrong: The world, she says, is actually resting on the back of a giant turtle. The learned man smiles and asks, “What is the turtle standing on?” The old lady doesn’t even blink and replies, “Another turtle, of course!” When the learned man starts to respond, “And what is that turtle—” she interrupts him: “You’re very clever, young man . . . but it’s turtles all the way down!”
Just like that cosmic stack of turtles, the process of justifying beliefs based on other beliefs never ends—unless at some point we manage to arrive at a belief that doesn’t rely on justification from any prior belief. That would be a foundational source of belief.
But this creates a paradox of its own: we can only justify a belief by basing it ultimately on source beliefs, and source beliefs by definition have no justifying beliefs. So the only way to justify a particular belief is to start with an unjustifiable belief.
It’s like getting down to the last turtle to find it resting on ... nothing at all.
How maddening! Instead of clarifying how we can decide what to believe, we’ve instead proven that the only way to justify beliefs is to acknowledge that certain principles must be accepted without justification.
But if we can’t justify these source beliefs, how can we figure out which source beliefs are the right ones? How do we know it’s this belief and not the one inside the next fortune cookie? The usual answer is simple: we choose the beliefs that we want to be true. But if we really care about justifying our beliefs, that’s hardly enough. We’ll have to wrestle with the paradox.
One approach to this challenge is to treat the problem the same way mathematicians approach proofs: they determine a core set of assumptions and then prove theorems based on those assumptions. Instead of presuming source beliefs are beliefs based on faith, let’s instead regard them as the starting assumptions for a logical proof. We can put forth a set of core assumptions and then develop a broader system of belief based on those assumptions. If the resulting system fails to create a cohesive and comprehensive system of belief, then we can start over. The initial assumptions can then be reformulated until a set is found that does lead to a consistent, meaningful “theorem of life.”
As an example of this process we can look at an age-old question confronted by mapmakers: What is the maximum number of colors needed to color a map so that no two regions—whether countries, counties, or any other shapes—share both a border and a color? In 1852, a student at the University of London named Francis Guthrie took on the challenge while coloring a map of English counties. He realized that, despite the convoluted shapes of some counties and the fact that each shares borders with many other counties, no more than four colors seemed necessary. If he would alternate colors between adjacent neighboring counties he found that he didn’t need more than four colors to complete the map. So he made an intuitive assumption that only four colors were sufficient for any map or combination of shapes, real or manufactured, no matter how complex or how arranged. If his assumption were correct, you could throw a handful of cutout shapes on a table—triangles, snowflakes, wavy lines, whatever—and need no more than four colors to color the resulting mess.
The four-color theorem, as it was known, was simple to test but devilishly hard to prove. Generations of mapmakers after Guthrie tested it with every map they made, and sure enough, no one ever needed a fifth color. But this was not the same as proof, of course. There was always the possibility that the next map would need more than four colors. Still, even though the assumption could never be entirely proven by real-world testing, with every successful application of the theorem, the odds of such an exception diminished, and confidence in it justifiably increased.
It wasn’t until 1976 that a team of mathematicians at the University of Illinois finally harnessed the power of a computer to solve the theorem. (Interestingly, another, more powerful computer was required to test the solution of the first, and that wasn’t achieved until 2005.)
Like the four-color theorem, an unproven assumption can be tested to see if it generates a coherent result. The more it does so, the more the confidence in that theorem may increase—even if it is never fully proven.
The approach of treating starting beliefs as assumptions removes the predicament of not knowing how to pick and choose between unjustifiable beliefs. If these beliefs are going to be rudimentary enough to form the basis of any belief system, no other system can be used to pick them because such a system would then become a core belief itself. By adopting the notion of starting assumptions, there’s no need to be forced to choose source beliefs. Rather, different combinations of these beliefs can be evaluated in light of the results they yield.
As you will see, the heuristic of this entire book is that we need to be willing to reassess our lives with empirical checks. We need to continuously test our assumptions rather than presuppose them. We must look at everything with fresh eyes and not adopt the biases of others.
Tools for Evaluating Assumptions
Two other ideas may be useful in selecting a set of starting assumptions. The first is to favor simplicity. This is called Ockham’s razor, after the fourteenth-century philosopher and theologian William of Ockham. The “razor” refers to any principle that helps narrow possibilities. This principle states that the answer that requires the fewest assumptions while explaining all of the facts is most likely to be correct.
For example: after taking a stroll one evening, you notice that the lights are on in your apartment. You come up with two possible explanations:
- You forgot to turn them off when leaving the house.
- Your neighbor was baking cookies and didn’t have milk at home, so he came into your apartment to borrow milk, turned on the lights when he came in, and never turned them off when he left.
The first hypothesis requires only one assumption—that you forgot to turn the lights off. The second hypothesis requires several assumptions—that your neighbor was baking cookies, wanted milk to go with the cookies, didn’t have any milk, thought your apartment was the best place to get some, was able to get into your apartment, and left the lights on when he was finished. Both would explain the facts you can see, but if we apply Ockham’s razor, we would favor the first hypothesis since it requires fewer assumptions.
If we apply the razor to our search for source beliefs, it follows that a system of beliefs that requires fewer source beliefs has a greater likelihood of being valid. In other words, the fewer leaps of faith (unjustifiable source beliefs) required in order to create a system of belief, the less faith we need and the more confident we can be in the outcome.
Of course, it’s possible to misuse this concept—typically by ignoring the requirement to explain all the facts. For example, the hypothesis that height alone determines a person’s weight is a lot simpler than the notion that the complex interplay of a few dozen genes, diet, and exercise does so. But the simpler explanation fails to explain all the facts—namely, the stunning range of actual variation we see in real-life height-to-weight ratios. The five-foot-five sumo wrestler who weighs a hundred pounds more than the six-foot-nine basketball player presents an instant (and fatal) problem for the simpler answer. Thus, simpler is better so long as it explains all the facts.
A second tool for choosing basic source beliefs is to think about what it would mean to deny a particular source belief. In other words, if a particular belief were not true, would the resulting worldview make sense? To return to the mapmaker’s problem, the very first map that required five colors would have rendered the four-color theorem invalid.
There are often logical consequences to accepting or rejecting an assumption, even if it can’t be justified with prior assumptions. Evaluating the consequences of beliefs can be helpful in determining what type of assumptions may be needed to form a valid system of belief.
We have to be careful with this tool as well. The best example of its misuse might be the “argument from consequences.” God’s existence is often assumed to be true because so many people think the consequences of his nonexistence would be terrible.
But you can’t argue that something is false solely because it produces consequences that are not good. Otherwise you’d have an argument that the Holocaust never happened because the world would be better if it hadn’t. On the other hand, you can argue that something is false because it produces consequences that are not true.
The Most Basic of Assumptions
At this point, our discussion is limited to beliefs about what facts we should believe. Later we’ll approach the more complex but essential question of how we should behave.
We propose that to develop a coherent framework of factual belief, we need to accept three core assumptions:
- An external reality exists.
- Our senses perceive this external reality.
- Language and thought are tools for describing and understanding what our senses perceive.
In the study of philosophy, the belief in the above three assumptions is known as “perspectival realism.” These three assumptions are so elemental that we take them for granted in our everyday lives. But it’s worth examining them in some depth since they will form the cornerstone of all subsequent beliefs we will discuss.
A belief in an external reality is the acceptance that the world, universe, and everything in it physically exist and are real. It is a belief that the world is independent of the way any individual thinks about it. The opposite would be to believe in a mind-created reality, or a reality that resides solely in our minds or our dreams.
It is not possible to definitively prove that the world we exist in is indeed an external reality. Reality is perceived only through the perspective of the mind, so the whole thing could just be an illusion. But the reality is that in daily life, we all assume that objects we see actually exist and that our fellow humans can also interact with and perceive them. Anyone who feels uncomfortable with accepting the notion of an external reality should ask why, when leaving a two-story building, he or she would rather walk down the stairs than take a shortcut by just hopping out the window. In real life, we don’t jump out of windows thinking we’ll just float down to the sidewalk unharmed, and we certainly don’t behave as if reality were just a figment of our imaginations. Rather, our daily actions show that we take for granted that the world around us is real and that we exist within it.
The existence of an external reality allows for a much greater concept —that “truth” is simply an accurate description of what is. It is our contention that reality and truth are the same thing. The world that exists around us right now is a truth. The fact that the air we inhale with each breath consists mostly of nitrogen and oxygen is a truth. The audible words that someone says are a truth. What that person actually means by those words is a truth as well, whether or not others know it. A truth or fact is simply an accurate account of reality. A belief in the contrary—in a subjective view of reality—would deny the existence of facts or certainties. From that perspective, truth becomes a relative concept. My truth—not just my opinions or experience, but my actual truth in apprehension of the universe—could be different from yours.
Consider an example of two friends, both passionate fans of a college basketball team that finished an exciting, record-setting season but lost the conference championship in a squeaker. One claims that the season was as a huge success because the team won most of its games and played better than ever before. But the other claims that the season was a failure because they lost the most important game—the championship. Each friend offers differing interpretations of the season, and they even offer different views on what events actually took place in some of the games. But a set of facts exists and is real, whether or not the friends see eye to eye and regardless of their different interpretations—games won and lost, points scored, assists, fouls, the works. The facts happened, even if people differ on what those facts meant.
That is what it means for truth and reality to be one and the same.
Using Our Senses
The second core assumption is that our senses—our eyes, ears, sense of touch, smell, and taste—perceive the external reality around us. Our eyes see a table because a table exists in reality. In theory, this is something we can never prove—that a table really exists or that an object that appears round is truly round. We have no other source of information about whether our perception is accurate.
Bertrand Russell explored the relationship between our senses and reality in his book The Problems of Philosophy. We never perceive the world directly, Russell said—we perceive our sense-data, and they in turn perceive the world. The fact that our senses are forever standing between us and reality poses a problem because our senses can be misled by changing conditions or by our state of mind. A table that appears red in the morning can look brown at noon and purple at dusk. It can look huge in a small room and tiny in a cavernous one. Press on the table with your fingertips, and you’re not feeling the table—you’re feeling the sensation of your fingertips being compressed. Or at least you think you are, since any number of things can cause you to experience that sensation. Do you really know that a table is causing that feeling, or is it all in your mind?
Maybe there’s no table there at all!
Just about the time Russell has us doubting the existence of tables (and everything else), he rescues reality. Even if a hundred different people describe a given table in a hundred different ways, he reminds us, they can usually agree that they are in fact looking at a table. That common denominator suggests that our confidence in the table’s existence is justified, even if we can’t quite sort out the details of color, texture, and size. And even if we disagree on everything else, we can accept that it has these attributes—it has a color, a texture, and a size. And our senses, limited as they are, represent our best chance of discovering the truth about those attributes.
Of course, in everyday life we take for granted the validity of what our senses perceive since we interact with the world all around us. This core assumption further implies that our only source for making assessments about what is true or not, what exists in reality and what does not, is our senses. To rephrase, if we can’t perceive something or its effects without the use of our senses, then we have no ability to evaluate whether or not it’s true.
It goes without saying that the ability of our senses to perceive reality can be greatly enhanced and extended through the use of tools, instruments, and technology. Millions of people see the world around them with better clarity and detail because of their eyeglasses or contact lenses. Scanning electron microscopes let us see tiny objects such as a single hair on the leg of a housefly. Ultrasounds can peer through the womb of a mother to reveal the developmental stage of a fetus. Radar can alert us of aircraft hundreds of miles away. The use of tools and instruments to derive knowledge about the world is commonplace.
But all of these instruments have one crucial thing in common: they all translate their acquired information into a form that we can perceive through our rudimentary senses. It is still our senses alone that ultimately allow us to perceive what these instruments detect. We also rely on our senses to confirm the accuracy of these tools. Looking in the sky for an airplane can validate radar. Looking at the newborn child can confirm the ultrasound diagnosis.
Of course, our senses are not infallible, in part because our minds interpret what we see and can therefore bias our perceptions. Still, aside from people who have mental disorders, what we perceive with our senses is generally accurate. For example, when one looks at a spoon that is placed inside of a glass of water it may appear bent. Although we know that the spoon is not really bent, but refracted, the observation that the spoon appears bent is an accurate reflection of what is real. The problem is not with the ability of our senses to observe reality but with the conclusions the mind may draw from what is seen. So if a person thought the spoon actually was bent, that would be a false conclusion based on a misinterpretation of good data. Our senses’ abilities to feel the spoon in the water confirms that it is indeed as straight as it was before it went into the glass.
We will deal more with how we should process the information our senses receive and how to deal with conflicting information about what to believe later in the book. At this point it’s enough to say our senses are the only source for ascertaining what is real and what is not in the external reality (despite their deficiencies).
The senses we are referring to include only the five rudimentary senses of sight, touch, hearing, smell, and taste. Why not include other senses such as a “sixth sense” (extrasensory perception) or the “heart” (intuition) as part of the list of senses that inform us about what exists in this world? We will deal with this issue more explicitly in forthcoming sections. For now, let’s see how much progress can be made by accepting only the five biological senses.
Using Our Minds
The last core assumption we propose is that language and thought are tools for describing and understanding what our senses perceive. The phrase “language and thought” will be used throughout the book to represent a broad range of more nuanced terms, including language, words, semantics, logic, mathematics, statistics, thought, mind, and intellect. This assumption requires us to think about words, definitions, and other concepts in ways that may be unfamiliar. But it is critical for the steps to come, so let’s take it slowly and break things down for better comprehension.
Language, words, semantics, logic, mathematics, statistics, thought, mind, the intellect, and the like can be lumped together since they can be viewed as one and the same—tools used to communicate meaning. Such tools create necessary starting points for discourse, and their validity is rooted in their definitions. Consider language for a moment. In order to even ask the question, “How can one justify one’s beliefs?” there needs to be agreement on what the words belief and justify mean.
Agreement is at the heart of language. Unlike physical reality, there’s no inherent “truth” about the meaning of a certain word, and there’s no universally right word for a given thing or idea. A word means what we mutually agree it means. Reality is independent of our ideas and perceptions of it, but language is entirely dependent on them. There can be many correct words for a single thing (hello, bonjour, guten tag, hola, shalom, néih hóu), and conversely a single sound can mean different things to speakers of different languages. The long i sound, for example, means eye in English, yes in Scots, and egg in German—each the result of subjective agreement in that culture.
For another example of the nature of language, we can turn to the language of mathematics. The Pythagorean theorem asserts that the sum of the squares of the sides of a right-angled triangle equals the square of the hypotenuse. This is true not because there is some inherent wisdom in the assertion but because the definitions of sum, squares, equal, and triangle make that statement coherent. It may take the mind of a genius like Pythagoras to demonstrate some of the principles of mathematics, but the proof of the resulting theorem does not require a leap of faith—it just requires an understanding of how we have defined those terms.
These definitional truths can further be used to describe real objects in the external reality—the length of a triangle drawn on paper can represent the measurement of an actual triangular object that exists in the world. Were we not to accept the validity of these tools, we would lack an ability to form any thoughts, concepts, or principles based on what we observe through our senses.
This core assumption in definitional truths also includes the use of our minds and intellect to manipulate and process thoughts and data. The power of our mind allows us to define language and objects, manipulate numbers, and develop rules. By accepting the validity of this assumption, we also accept the use of language and thoughts to derive other facts and information that may not initially be clear to us. We can then use these conclusions to reflect back on the external reality. This ability to switch between reality and our description of reality allows us to formulate far more sophisticated concepts and notions than just simple observations. So part of the acceptance of this assumption means also accepting the ability of our minds or intellects to organize thoughts, to find links between thoughts, and to draw conclusions.
The First Three Non-commandments
Where does accepting these three basic assumptions really get us? After all, most of us accept these notions in our everyday lives without feeling the need to ascribe all of this significance and nuance.
But here’s why they are so important: from these three assumptions alone, it’s possible to derive many, many more beliefs. These assumptions and derived beliefs will help us formulate a framework of beliefs, including Ten Non-commandments for the Twenty-first Century.
The commonsense nature and seeming simplicity of these assumptions allow us to accept them at a glance. But that very simplicity might be mystifying. Can these three assumptions really be all we need to justify our beliefs? Hang on to that question, and we’ll see soon enough.
To rephrase the three core assumptions in light of the concepts we have just discussed, our starting assumptions are:
- An external reality exists, and “truth” signifies an accurate description of that reality.
- Our five senses are our only means for perceiving this reality.
- Language and thought offer ways to analyze, communicate about, and contemplate the nature of the reality.
These core assumptions can be summed up as (1) a belief in existence, (2) an ability to perceive that existence, and (3) instruments for using those perceptions.
There’s still some work to do to determine whether these three core assumptions are really all we need. For one thing, we need to see what other beliefs can be derived from these assumptions and test whatever system of belief arises from them. Only when we have a complete, tested system can we be satisfied that our initial assumptions are sufficient. For now, to keep things moving forward, we only ask that you give us the benefit of the doubt that the beliefs being proposed will yield a valid outcome. There’ll be plenty of time to change your mind if you so choose.
Because these three assumptions are the bedrock beliefs of all subsequent beliefs we will propose, they will serve as the first three non-commandments:
- I. The world is real, and our desire to understand the world is the basis for belief.
- II. We can perceive the world only through our human senses.
- III. We use rational thought and language as tools for understanding the world.
Excerpted from "Atheist Mind, Humanist Heart" by Lex Bayer and John Figdor. Copyright © Rowman & Littlefield. Used by arrangement with the publisher. All rights reserved. No part of this excerpt may be reproduced or printed without permission in writing from the publisher.