The Skeptics' Guide to the Universe: How to Know What's Really Real in a World Increasingly Full of Fake

by Steven Novella

There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another which states that this has already happened. —Douglas Adams

We all start as children believing pretty much whatever we’re told. The gulf of knowledge and experience between adults and young children is so great that to a child, any adult is perceived as the ultimate authority on any topic. As we mature we realize that not all adults agree with each other, so some of them must be wrong.

This is the essence of skepticism: How do we know what to believe and what to doubt?

It’s intimidating to realize that we live in a world overflowing with misinformation, bias, myths, deception, and flawed knowledge. We are all children and there are no adults. There are no ultimate authority figures; no one has the secret; there is no revealed knowledge; and there is no place to look up the definitive answers to our questions (not even Google). We are all struggling through this complex universe just like everyone who came before us. Fully realizing this essence of the human condition can make you cynical, denying all knowledge. That, however, is just another bias, another narrative to help us deal with the chaos. Cynicism is also cheap—it’s easy just to doubt or deny everything. But it doesn’t get you or society anywhere. Skepticism goes beyond cynicism. While it may start with doubt, that’s the beginning, not the end. There isn’t any definitive or ultimate knowledge (no Truth with a capital T), but we can grind out knowledge about the world that is sufficiently reliable for us to treat it as provisionally true and act upon it.

we can slowly and carefully build a process by which to evaluate all claims to truth and knowledge. A big part of that process is science, which systematically tests our ideas against reality, using the most objective data possible. Science is still a messy and flawed process, but it is a process. It has, at least, the capacity for self-correction, to move our beliefs incrementally in the direction of reality. In essence, science is the process of making our best effort to know what’s really real. Combined with science are logic and philosophy, which are simply ways of thinking about things really carefully, to at least make sure there is no internal contradiction. Valid reasoning, careful and systematic observations, recording and counting all data (not just the data we want), and trying to disprove our own conclusions is a lot of work, but it moves us forward on our journey. Skeptics combine knowledge of science, philosophy, human psychology, and all the flaws and biases of human thinking to evaluate all claims and beliefs, especially their own.

Don’t panic. This whole notion of thinking for yourself and questioning everything is actually quite fun and empowering. We can do this together.

The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what’s true. —Carl Sagan

These tools—your core concepts of scientific skepticism—can be broken down into four categories. The first set of skills comprise what I like to call “neuropsychological humility.” This category includes knowledge of all the ways in which your brain function is limited or flawed.

The second category of skeptical “gear” is called metacognition—thinking about thinking. Metacognition is an exploration of all the ways in which your thinking is biased.

The third type of skeptical equipment has to do with science—how it works, the nature of pseudoscience and denialism, and how science can go wrong.

The fourth category of core concepts takes you on some historical journeys, reviewing iconic examples of pseudoscience and deception as cautionary tales.

A scientific skeptic provisionally accepts a claim only in proportion to its support from valid logic and a fair and thorough assessment of available evidence. A skeptic also studies the pitfalls of human reason and the mechanisms of deception so as to avoid being deceived by others or themselves. Skepticism values method over any particular conclusion.

Philosophers focus on how to think in a clear, precise, unambiguous, and internally consistent way. Science works within a philosophy of methodological naturalism (all effects have natural causes) and uses a refined set of methods to check our theories against reality.

We are scientific skeptics because we start with doubt, but we then carefully try to separate what we can and do know from fantasy, wishful thinking, bias, and tradition.

Here are the tools and methods scientific skeptics use to help them parse reality: Respect for Knowledge and Truth—Skeptics value reality and what is true. We therefore endeavor to be as reality-based as possible in our beliefs and opinions. This means subjecting all claims to a well-founded process of evaluation. Skeptics believe that the world is knowable because it follows certain rules, or laws of nature. The only legitimate method for knowing anything empirical about the universe follows this naturalistic assumption. In other words, within the realm of the empirical (factual knowledge based on evidence), you don’t get to invoke magic or the supernatural.

Promotion of Science—Science is the only set of legitimate methods for investigating and understanding the natural world. Science is therefore a powerful tool—and one of the best developments of human civilization. Those of us who choose to be activists promote the role of science in our society, public understanding of the findings and methods of science, and high-quality science education. This means protecting the integrity of science and education from ideological intrusion or antiscientific attacks. It also involves supporting high-quality science, which requires examining the process, culture, and institutions of science for flaws, biases, weaknesses, and fraud.

Promotion of Reason and Critical Thinking—Science works hand in hand with logic and philosophy, and therefore skeptics also promote better understanding of...

...these fields and critical thinking skills.

Science vs. Pseudoscience—Skeptics are the first, and often the last, line of defense against incursions by pseudoscience. In this role, we seek to identify and elucidate the borders between legitimate science and pseudoscience, to expose pseudoscience for...

...what it is, and to promote knowledge of how to tell the difference.

Ideological Freedom / Free Inquiry—Science and reason can only flourish in a free society in which no ideology (religious or otherwise) is imposed upon individuals or the process of science and free inquiry.

Neuropsychological Humility—Being a functional skeptic requires knowledge of the various ways in which we deceive ourselves, the limits and flaws of human perception and memory, the inherent biases and fallacies in cognition, and the methods that can help mitigate all these flaws and biases.

Consumer Protection—Skeptics endeavor to protect themselves and others from fraud and deception. We do this by exposing fraud and educating the public and policy makers to recognize deceptive or misleading claims or practices. In a...

...addition, skeptics tend to be a source of institutional memory.

Cognitive psychology tells us that the unaided human mind is vulnerable to many fallacies and illusions because of its reliance on its memory for vivid anecdotes rather than systematic statistics. —Steven Pinker

Everything we personally know about the world is memory.

Our memories serve more to support our beliefs than to inform them. In a way, they are an evolving story we tell ourselves.

There is declarative memory (also called explicit memory), which is factual knowledge stored in long-term memory and consciously recalled.

Procedural memory (also called implicit memory) is more automatic and involves learning how to do motor tasks such as throwing basketballs or writing in script.

Episodic memory is memory of events and our o...

...own experiences.

Semantic memory is factual memory about the world, not specific to your own experiences.

Memories are flawed from the moment we construct them, but they’re also not stable over time. Each time we recall a memory we are actually reconstructing and updating it. Memory, like perception, emphasizes internal consistency. We alter memories to fit our internal narratives about reality, and as those narratives change, we update our memories to fit them.

Fusion—We can fuse the details of different memories, mixing them up or even combining two separate memories into one.

Confabulation—Put simply, we make shit up. This is a completely automatic and subconscious process. Again, our brains want to construct a continuous and consistent memory, so if there are any missing pieces it just makes them up to fill in the gaps.

In a 2010 study by Isabel Lindner et al., researchers found that simply observing another person performing an act can create false memories that we performed that act. They report: In three experiments, participants observed actions, some of which they had not performed earlier, and took a source-memory test. Action observation robustly produced false memories of self-performance relative to control conditions. This research follows other research demonstrating that imagining an event is often enough to create the false memory of that event. Imagination activates many of the same brain areas that a true memory would. In essence, a memory of the imagination may over time become indistinguishable from a memory of a real event—and a false memory is born.

Personalize—There is a tendency to shift memories from happening to other people to happening to ourselves. If someone tells us an emotionally gripping tale of an encounter, months or years later we may remember ourselves in the starring role, or at least as a direct witness.

Contamination—We are social creatures. Part of our social nature is that we place high value on the testimony of others. When people discuss an event together, sharing the details of their individual memories, they are likely to contaminate each other’s memory. People will take details offered by someone else and seamlessly incorporate them into their own memories.

Distortion—Details of a memory can also simply change or be distorted. The details may drift over time, or they may change in a way specifically to support the emotional narrative of the memory. Memories can be distorted by suggestion. Merely suggesting a detail to someone while they are recalling a memory may cause them to incorporate that detail into their memory.

The clear lesson here is that we all need to be humble when it comes to the accuracy of our own memories. As we will see, failure to appreciate the true nature of memory can create great mischief.

Our beliefs do not sit passively in our brains waiting to be confirmed or contradicted by incoming information. Instead, they play a key role in shaping how we see the world. —Richard Wiseman

We’re a bit freaked out by really good optical illusions because they force us to directly confront a reality we tend to ignore as we go through our daily lives: What we think we see is not objective; it is a process of our brains, and that process can be fooled.

The bottom line is this: Your real-time perceptions are not a passive recording of the outside world. Rather, they are an active construction of your brain. This means that there is an imperfect relationship between outside reality and the model of that reality crafted by your brain. Obviously, the model works well enough for us to interact with that reality, and that’s actually the idea. Constructed perception is not optimized for accuracy but rather for functionality.

The lesson here is that even the most basic components of your existence are actively constructed by your brain. Each component can be disrupted and erased. How does all this affect critical thinking? Well, just as with memory, be wary of saying, “I know what I saw.” Hmm… no, you don’t. You have a constructed memory of a constructed perception based on filtered partial sensation and altered by your knowledge and expectations. Psychologists have recognized some specific and dramatic manifestations of the limits of human perception.

Pareidolia refers to the process of perceiving an image in random noise, such as seeing a face in the craters and maria of the moon.

If you look at any walls spotted with various stains or with a mixture of different kinds of stones, if you are about to invent some scene you will be able to see in it a resemblance to various different landscapes adorned with mountains, rivers, rocks, trees, plains, wide valleys, and various groups of hills. You will also be able to see diverse combats and figures in quick movement, and strange expressions of faces, and outlandish costumes, and an infinite number of things which you can then reduce into separate and well-conceived forms. —Leonardo da Vinci

sometimes the term is used to refer to other sensations, such as sound (in which case it might be called, fittingly, audio pareidolia).

The technical term for the more general phenomenon of seeing patterns where they do not exist is apophenia, the tendency to see illusory patterns in noisy data.

prosopagnosia, which is an inability to recognize faces.

Pareidolia can be fun, but if you aren’t aware of our penchant for and love of patterns, an interesting and diverting illusion can feed into a delusion.

There is a very remarkable inclination in human nature to bestow on external objects the same emotions which it observes in itself, and to find everywhere those ideas which are most present to it. —David Hume

I think it’s liberating to understand that in most situations, rather than there being an invisible supernatural or implausible agent at work, the simpler explanation is that (as was most elegantly stated on a bumper sticker) “shit happens.”

Hypnagogia is a neurological phenomenon in which the dreaming and waking states are fused, producing unusual experiences often mistaken for paranormal ones.

Hypnagogia is a neurological phenomenon that can occur when a person is waking up (hypnopompic) or going to sleep (hypnagogic). It’s an in-between state where the person is neither fully awake nor fully asleep. In this state, very realistic images and sounds can be experienced. Although visual and auditory hallucinations are most common, experiences can range from hearing your name whispered to ones involving all the senses, including touch. They are, in essence, dream experiences that are occurring while you’re semi-awake. These waking dreams can be bizarre and terrifying.