Elementary, My Dear Watson*

When you’re trying to solve a complex problem, determine a course of action, or evaluate others’ conclusions, you’ll need to engage logical System 2 reasoning, which is the opposite of System 1’s quick assessments.

I never guess. It is a shocking habit—destructive to the logical faculty. —Sherlock Holmes in The Sign of Four

It can be helpful to understand different types of reasoning, be able to identify the type—or types—of reasoning that are being applied in a given situation, and know how accurate each type is likely to be.

But recognizing and/or applying a reasoning process to your problem or evaluation process isn’t enough to guarantee that the outcome of that reasoning process will be sound or accurate. Skillful reasoning doesn’t compensate for faulty premises or missing or biased information.

The following descriptions (but not the examples) of deductive, inductive, and abductive reasoning were provided by Alina Bradford, writing in Live Science (livescience.com).

Deductive reasoning: conclusion guaranteed

Deductive reasoning is a basic form of valid reasoning. Deductive reasoning, or deduction, starts out with a general statement, or hypothesis, and examines the possibilities  to reach a specific, logical conclusion, according to the University of California. The scientific method uses deduction to test hypotheses and theories. “In deductive inference, we hold a theory and based on it we make a prediction of its consequences. That is, we predict what the observations should be if the theory were correct.  We go from the general—the theory—to the specific—the observations,” said Dr. Sylvia Wassertheil-Smoller, a researcher and professor emerita at Albert Einstein College of Medicine.

In deductive reasoning, if something is true of a class of things in general, it is also true for all members of that class. For example, “All men are mortal. Harold is a man. Therefore, Harold is mortal.” For deductive reasoning to be sound, the hypothesis must be correct. It is assumed that the premises, “All men are mortal” and “Harold is a man” are true. Therefore, the conclusion is logical and true.


  • It is dangerous to drive on icy streets. The streets are icy now so it is dangerous to drive now.
  • All birds have feathers and robins are birds, so robins have feathers.
  • Elephants have cells in their bodies and all cells have DNA, so elephants have DNA.

[Caveat: Deductive inference conclusions are certain provided the premises are true. It’s possible to come to a logical conclusion even if the generalization is not true. If the generalization is wrong, the conclusion may be logical, but it may also be untrue. For example, the argument, “All bald men are grandfathers. Harold is bald. Therefore, Harold is a grandfather,” is valid logically but it is untrue because the original statement is false.]

Inductive reasoning: conclusion merely likely

Inductive reasoning is the opposite of deductive reasoning. Inductive reasoning makes broad generalizations from specific observations. “In inductive inference, we go from the specific to the general. We make many observations, discern a pattern, make a generalization, and infer an explanation or a theory,” Wassertheil-Smoller told Live Science. “In science there is a constant interplay between inductive inference (based on observations) and deductive inference (based on theory), until we get closer and closer to the ‘truth,’ which we can only approach but not ascertain with complete certainty.”

Even if all of the premises are true in a statement, inductive reasoning allows for the conclusion to be false. Here’s an example: “Harold is a grandfather. Harold is bald. Therefore, all grandfathers are bald.” The conclusion does not follow logically from the statements.


  • John is a financial analyst. Individuals with professions in finance are very serious people. John is a very serious person.
  • Jennifer leaves for school at 7:00 a.m. and is on time. Jennifer assumes, then, that she will always be on time if she leaves at 7:00 a.m.
  • The water at the beach has always been about 75 degrees in July. It is July. The water will be about 75 degrees.
Abductive reasoning: taking your best shot

Another form of scientific reasoning that doesn’t fit in with inductive or deductive reasoning is abductive. Abductive reasoning usually starts with an incomplete set of observations and proceeds to the likeliest possible explanation for the group of observations (Critical Thinking Skills, Butte College). It is based on making and testing hypotheses using the best information available. It often entails making an educated guess after observing a phenomenon for which there is no clear explanation.

Abductive reasoning is useful for forming hypotheses to be tested. Abductive reasoning is often used by doctors who make a diagnosis based on test results and by jurors who make decisions based on the evidence presented to them.


  • Given a particular set of symptoms, a medical doctor needs to determine the diagnosis that would best explain most of them.
  • Jurors have to decide whether the prosecution or the defense has the best explanation to cover all the points of evidence although additional evidence may exist that was not admitted in the case.

While using one of these three types of reasoning is a function of System 2 (conscious) cognition, evaluating them—and their results—is an example of metacognition, which is a higher order of System 2 cognition. Metacognition is a skill you can develop to help you think smarter and improve outcomes in all areas of your life.

I cannot live without brain-work. What else is there to live for? —Sherlock Holmes in The Sign of Four

*This quintessential Sherlock Holmes quote was never actually uttered in any of Conan Doyle’s stories about him.

W Is for Writing

Writing is such an effective tool for change that I use it in all of my classes and workshops. It can help you clarify intentions or goals and assist you in staying on track. It’s also extremely useful for helping you calm down, focus, and develop clarity about troubling or difficult issues.

The pen compels lucidity. —Robert Stone, novelist

The catch is that in order to get the best results, you need to be clear from the outset about what you want from your writing. You could just fill page after page in a notebook (something I did for quite a few years until I chucked the lot), but after you’re finished you may not be any clearer than you were to begin with. You might even be more confused.

Starting out with a question or prompt, maybe just a keyword or key phrase, can allow you to access some of the thoughts that may be swimming below the surface. Using a multi-part exercise can help you get even deeper and reap greater rewards.

The two basic approaches to writing—flow writing and deliberate writing—involve using the two different parts of the brain (System 1 and System 2). The problem with completely unstructured writing is that it can muddle these two approaches so that you don’t get the full benefit of either.

Flow Writing:
Making Use of Associative Thinking

The unconscious (System 1) excels in associative thinking. It detects patterns and connects dots quicker than the conscious part of your brain (System 2) can. It’s a fast processor that sometimes sacrifices accuracy for speed. But it also has access to lots of information the conscious brain isn’t aware of.

Flow writing, which is also called free writing, is non-linear, non-rational, and non-logical. You put your pen to paper and write quickly, letting the words “flow” without censoring or editing them. You don’t stop to think about what you’re writing. The best way to free your mind for flow writing is to set a page limit or use a timer.

Flow writing is a good choice if you’re not entirely sure what the problem is. If you have a lot of thoughts swirling around in your head, you can get them down on paper and take a look at them. But even with flow writing, you’ll get better results if you begin with a specific question, prompt, or keyword.

Deliberate Writing:
Making Use of Logical, Linear Thinking

The conscious part of the brain is rational, logical, and linear. It operates at a much slower—more deliberate—speed than the unconscious. A good way to engage conscious thinking is to respond to a series of questions or prompts. While flow-writing casts a wide net in search of answers or information, deliberate writing narrows the search.

This 8 Step Problem-Solving exercise is an example of using deliberate thinking to gain clarity. You proceed through the sequence of questions or statements with the intention of reaching some resolution.

Integrated Writing:
Making Use of Both Kinds of Thinking

Sometimes flow writing or deliberate writing alone is sufficient, but integrating them can be much more powerful. Integrated writing is synergistic rather than additive, which means the whole (the result) is greater than the sum of the parts you used to get there. A few examples of integrated writing include:

10 minutes of flow writing (System 1 associative thinking) followed by writing the answers to a series of questions (System 2 logical, linear thinking). You can create your own set of questions or use the ones in the 8 Step Problem-Solving exercise.

Write Your Way Out of the Story. For instructions scroll to Antidote #3 in this post on rumination.

Go Deeper: This is a 4-part exercise that’s best to do in one sitting. Begin by writing a question at the top of a blank page and then flow write in response to it for 8-12 minutes. Next, reread what you wrote (engaging System 2), select a sentence or phrase, and write it at the top of another blank page. Flow write in response to this sentence or phrase for 8-12 minutes. Finally, reread both pieces (System 2), find a question—either one you asked in your writing or one that occurs to you after reading—write it at the top of a blank page, and flow write in response to it for 8-12 minutes. Then reread all three pieces and write a one-paragraph summary (System 2).

No matter which type of writing you decide to use, remember to have an intention. Be clear about what you’re doing and what you want to get out of your writing.

Practice, Practice, Practice

Even if writing doesn’t come naturally to you or seems like punishment, if you want to create habits that serve you, follow through on your goals and intentions, and develop your self-awareness, it’s worth exploring and experimenting with it.

As with any tool you want to master, regular practice makes all the difference. When you set and keep the same general time and place to write, you encourage (or prime) your brain to respond.

When you go into a restaurant, your brain is focused on deciding what to eat. When you get into your car, your brain is focused on driving. This is one of those obvious things you probably don’t really think about it. When you go into the restaurant, your brain is not focused on driving because it isn’t presented with environmental cues related to driving.

Another reason for developing a writing practice is that the real benefits of writing are cumulative. They are gained over time, not as the result of any individual exercise or piece of writing.

Part of the series A-Z: An Alphabet of Change.

Uncertainty: Learning to Live with Butterflies


The unconscious part of our brain abhors ambiguity and uncertainty. And patience is not its middle name. That’s unfortunate.

We work to eliminate as much uncertainty as we can as quickly as possible. But when we eliminate uncertainty, we necessarily eliminate novelty. And novelty is the starting point for creation and innovation. In eliminating uncertainty, we kill our shot at brilliance. We become derivative. All in the name of not having to learn to live with butterflies. —Jonathan Fields

In our haste to return to the illusory state of certainty, we tend to do things like jump to conclusions, accept the first answer or explanation that comes to mind (consistent with our mental model), act prematurely, or immobilize ourselves in endless rounds of rumination. (Rumination feels like problem-solving but it’s the opposite: problem-prolonging, if you will.)

By refusing to allow ourselves to simply observe the discomfort that accompanies ambiguity and uncertainty, we often deny ourselves another experience: the pure joy of the aha! moment when a solution presents itself. That may take an hour or several days—or even longer—but suddenly what was murky and inchoate becomes bright and clear. The path ahead becomes obvious.

I say the solution “presents itself” because although we tend to take credit for coming up with the brilliant idea or flash of insight, the part of our brain we identify with had little to do with it. It’s the unconscious that figured it out and then clued us in.

It’s interesting that the unconscious is equally capable of jumping to quick conclusions and of wrestling with an issue long after we’ve depleted our conscious capacity to think about it. In situations where a wrong conclusion isn’t likely to make a huge difference, jumping to one is probably more efficient. But when the issue or problem or project is bigger, it’s worth letting the unconscious mull it over for a while.

One of the reasons waiting this process out makes us squirm is that we have no control over it. It isn’t going to occur by the force of our will or on our timetable. When we try to make it happen we usually just end up getting in our own way and muddling the process.

Certainty Is Not Clarity

Although we frequently use the terms interchangeably, certainty is not a synonym for clarity.

Certainty itself is an emotional state, not an intellectual one. To create a feeling of certainty, the brain must filter out far more information than it processes. In other words, the more certain you feel, the more likely you are wrong. –Steven Stosny, Ph.D.

There’s a big difference between being unclear—not knowing which step to take—and being uncertain—not knowing what the outcome of taking that step will be. It’s important to distinguish between the two and to be able to recognize whether it’s a lack of clarity or the fear of uncertainty that’s getting in the way.

Certainty is an illusion—a somewhat comforting illusion, but an illusion nevertheless. There’s no way to predict the future, and randomness plays a much bigger role in our lives than we want to believe. So if we wait until we are certain of the outcome of our actions, we’ll never act because the outcome can never be certain. There are no guarantees in life.

The best laid schemes of mice and men often go awry. —Robert Burns

Clarity, unlike certainty, is not an emotional state. It’s a state of mind: unclouded, unobstructed, unambiguous. Clarity isn’t arrived at via a tortuous route. Unfortunately, since the unconscious part of our brain is biased against uncertainty, we are biased against it, too. This is another example of our brain using us instead of the other way around.

What you can do:

  • Practice tolerating uncertainty and not being attached to the outcome by adopting an attitude of curiosity.
  • Learn to distinguish between being unclear (not knowing which step to take) and being uncertain (not knowing what the outcome of taking that step will be).

It isn’t easy, but rather than trying to get back to comfortable and certain as quickly as possible, we can develop a tolerance for the discomfort. We can even learn to appreciate the uncertainty and the opportunity it presents for novelty. Whatever is on the other side of our current distress may be unimaginable to us now, but it could be brilliant. Why take the chance of missing out on something brilliant just to avoid feeling a little uncomfortable?

Additional reading: 12 Signs that You Lack Clarity

Overthinking: Don’t Get Stuck in Analysis Paralysis

spanish inquisitionIt’s one thing to look before you leap. It only makes sense to consider the potential outcome or consequences of an action you’re about to take. But it’s another thing altogether to believe you can fully determine—or even guarantee—the outcome based on the amount of thinking you do about it.

Overthinking often consists of making multiple lists of pros and cons, running through if/then scenarios, trying to gather as much information as possible, or attempting to approach the issue from every conceivable angle. The process of trying to make a decision becomes overwhelming. Worse, it drains conscious (System 2) attention throughout the period of time you’re trying to make a particular decision. So the more thinking you do about it, the less effective your thinking becomes. You can find yourself going around and around in mental circles, either unable to make the decision or just taking a stab at something—anything—because you can’t stand thinking about it any longer.

Overthinking also begets second-guessing, in which you get to run through several rounds of “if only/then” scenarios.

Overthinking is driven by your brain’s craving for certainty. But thinking harder or longer about something won’t necessarily get you closer to an answer. Here’s why:

  • In spite of your best efforts, your information will always be incomplete. There are things you don’t know, can’t know, or won’t know at the time you’re trying to decide, and any of those things could be important enough to affect the outcome. Unfortunately, we don’t know what we don’t know, and so we don’t take it into consideration.
  • Even if you were to have access to all of the information, because you’re human you’re subject to numerous cognitive biases, which means you won’t be able to view it entirely objectively. For example, you will overweigh some information and underweigh, or even ignore, other information. System 2 thinking may be what you’re aware of, but System 1 still has plenty of input, and System 1 makes mistakes.
  • You can’t account for randomness. The very idea of randomness makes your brain a little crazy, so it refuses to accept it. Your brain is under the impression it can find a cause-and-effect link for anything and everything. The consequences of randomness, according to physicist Leonard Mlodinow, are counterintuitive. (Nobody expects the Spanish Inquisition!)
  • You can’t predict the future. Even more to the point, you can’t predict how you’re going to feel in the future. Daniel Gilbert, in Stumbling on Happiness, says we tend to think the future will be a lot like today…only different. But the future is fundamentally different from today, and the way you feel right now when you think about the consequences of taking some action is not necessarily the way you will feel when you are living with the consequences of that action.
  • Taking any action can have unexpected results and undesired consequences. Although you can anticipate that such things might occur, you can’t plan for them because you won’t know what they are until after they happen.

Too much logical, linear thinking is as bad as too little. After framing the problem or situation and considering possible solutions, turn it over to your unconscious (System 1) for a while and see what it comes up with. Let your mind wander instead of keeping it on a tight leash. The sudden insight, moment of clarity, or change in perspective you get may surprise you. But this is the way the creative process works, and it’s a great way to use both parts of your brain to your advantage.

Additional reading: Intuition: Knowing without Knowing How We Know.

Intuition: Knowing without Knowing How We Know

associative thinkingIntuition goes by many names: hunch, gut feeling, instinct, inkling, inner voice. Malcolm Gladwell refers to it as “rapid cognition.” Cognitive psychologist John Bargh calls it “automatic processing.”

No matter how we label it, what intuition is is the ability to “know” something without knowing how we know it.

One thing intuition is not is magical or mysterious or superior in some way to rational, logical thinking. It’s just different. The world is not divided into people who are intuitive and people who are not. We all rely on intuition every day.

Intuition is the result of the associative thinking that takes place in the unconscious (System 1). The unconscious sees patterns and connects dots our conscious brain (System 2) isn’t even aware of. It operates quickly and it’s always on. That’s because, by the way, it’s what keeps us alive. And keeping us alive is what our brain is designed to do. System 1 makes rapid-fire assessments and communicates them to System 2. When we become consciously aware of one of those assessments, we call it intuition. We could also call it jumping to conclusions.

Jumping to conclusions on the basis of limited evidence is important to an understanding of intuitive thinking. System 1 is radically insensitive to both the quality and quantity of the information that gives rise to impressions and intuitions. —Daniel Kahneman

System 1 reacts exactly the same way (jumps to conclusions) whether we have a clue or not. So sometimes its assessments are accurate and sometimes they’re not. Intuition is good for making short-term predictions when it’s based on training, experience, and practice. But even when the training, experience, and practice are in place, intuition is not good for making long-term predictions or forecasts. There are just too many unknown variables for it to account for.

There are a number of potential problems related to relying on intuition. One is that System 1 processing is highly context-dependent. That means that whatever is going on at the time—the weather, our state of mind, the time of day, the last thing we ate—can influence our thoughts. So an intuitive assessment reached under one set of temporary circumstances could be entirely different from the one reached under a different set of circumstances.

Another problem is that good intuition in one area of our lives where we have expertise doesn’t carry over to other areas where we don’t have comparable expertise.

A third and bigger problem with intuition is the strong feeling of confidence it often engenders, whether or not that confidence is warranted, because that sense of confidence is all too easy to confuse with clarity.

What You Can Do:

Don’t automatically assume your intuitive guesses are accurate across the board. Just because you feel confident about something doesn’t mean you’re right. If you are skilled or knowledgeable in an area, your intuition is more likely to be accurate—at least when it comes to short-term predictions. But if  you have no particular skill or knowledge, your intuition isn’t any better than a wild guess.

As Kahneman says, “Do not simply trust intuitive judgment—your own or that of others—but do not dismiss it, either.”

Additional Reading: How Important Is Your Need to Be Right? and Do You Confuse Clarity with Certainty?