EppsNet Archive: Knowledge

Thinking, Fast and Slow by Daniel Kahneman

12 Dec 2014 /

The notion that we have limited access to the workings of our minds is difficult to accept because, naturally, it is alien to our experience but it is true: You know far less about yourself than you feel you do.

 

A reliable way to make people believe in falsehoods is frequent repetition, because familiarity is not easily distinguished from truth.

 

It is the consistency of information that matters for a good story, not its completeness. Indeed, you will often find that knowing little makes it easier to fit everything you know into a coherent pattern.

 

The exaggerated faith in small samples is only one example of a more general illusion — we pay more attention to the content of messages than to information about their reliability, and as a result end up with a view of the world around us that is simpler and more coherent than the data justify.

 

Narrative fallacies arise inevitably from our continuous attempt to make sense of the world. The explanatory stories that people find compelling are simple; are concrete rather than abstract; assign a larger role to talent, stupidity, and intentions than to luck; and focus on a few striking events that happened rather than on the countless events that failed to happen.

 

Hindsight bias has pernicious effects on the evaluations of decision makers. It leads observers to assess the quality of a decision not be whether the process was sound but by whether its outcome was good or bad. . . . This outcome bias makes it almost impossible to evaluate a decision properly – in terms of the beliefs that were reasonable when the decision was made.

 

Stories of how businesses rise and fall strike a chord with readers by offering what the human mind needs: a simple message of triumph and failure that identifies clear causes and ignores the determinative power of luck and the inevitability of regression. These stories induce and maintain an illusion of understanding, imparting lessons of little enduring value to readers who are all too anxious to believe them.

 

For some of our most important beliefs we have no evidence at all, except that people we love and trust hold those beliefs.

 

Confidence is a feeling, which reflects the coherence of the information and the cognitive ease of processing it. It is wise to take admissions of uncertainty seriously, but declarations of high confidence mainly tell you that an individual has constructed a coherent story in his mind, not necessarily that the story is true.

 

We know that people can maintain an unshakable faith in any proposition, however absurd, when they are sustained by a community of like-minded believers.

 

The idea that the future is unpredictable is undermined every day by the ease with which the past is explained. . . Everything makes sense in hindsight . . . And we cannot suppress the powerful intuition that what makes sense in hindsight was predictable yesterday. The illusion that we understand the past fosters overconfidence in our ability to predict the future.

 

[Philip Tetlock, a psychologist at the University of Pennsylvania] interviewed 284 people who made their living “commenting or offering advice on political and economic trends. . . . In all, Tetlock gathered more than 80,000 predictions. . . . Respondents were asked to rate the probabilities of three alternative outcomes in every case: the persistence of the status quo, more of something such as political freedom or economic growth, or less of that thing.

The results were devastating. The experts performed worse than they would have if they had simply assigned equal probabilities to each of the three potential outcomes. In other words, people who spend their time, and earn their living, studying a particular topic produce poorer predictions than dart-throwing monkeys who would have distributed their choices evenly over the options. Even in the region they knew best, experts were not significantly better than nonspecialists.

 

Rehearse the mantra that will get you significantly closer to economic reality: you win a few, you lose a few.

 

Nothing in life is as important as you think it is when you are thinking about it.

 

During the last 10 years we have learned many new facts about happiness. But we have also learned that the word happiness does not have a simple meaning and should not be used as if it does. Sometimes scientific progress leaves us more puzzled than we were before.


Teaching Computer Science: Exam Tips from the Pros

18 Nov 2014 /

When I cover something in a review session or study guide, it’s because I know it’s going to be on the test. There were questions during this morning’s test about the workings of several Java methods, all of which were covered in the review session and the study guide. I can’t answer questions like that during the test so if you have questions about review topics, ask them in advance of test day.

Some people seem to think that having an excuse for not knowing something is as good as actually knowing it. “But we hardly spent any time on Topic X in class.” “But we just learned Topic Y yesterday.”

Even if either one of those were true, what difference would it make? It’s on the study guide and it’s going to be on the test.

Given a choice between knowing something and having an excuse for not knowing it, always go with the first option: knowing it.


People Who Don’t Want Me to Know Things

12 Jul 2014 /

What I want to know is why there are so many people who don’t want me to know things . . .

Trudeau's book Natural Cures Updated Edition

And that doesn’t even include all the things that people “won’t tell me.”


To-Do List

26 May 2013 /
  1. Strive for clarity and distinctness.
  2. Ask “What do you mean, and how do you know?”

The Gettier Problem

28 Apr 2013 /
Edmund Gettier

Edmund Gettier

What does it mean to say that you “know” something is true?

According to traditional philosophical thinking, you can be said to know that some proposition P is true if and only if:

  1. P is true.
  2. You believe that P is true.
  3. You are justified in believing that P is true.

These three conditions jointly form the concept of justified true belief (JTB).

As an example, let’s examine my claim that I know Paris is the capital of France. Unless an edict to the contrary has come down in the last few minutes, Paris is the capital of France, I believe that Paris is the capital of France, and I’m justified in believing that based on available evidence. So according to the concept of justified true belief, I know that Paris is the capital of France.

Gettier Problems

Here’s a thought experiment: Let’s say I wake up in the morning, look at the clock (let’s make it an old-fashioned analog clock), and it shows the time as 7:30. And let’s say that the time is in fact 7:30, but that, unknown to me, the clock has stopped. Do I “know” that the time is 7:30? My belief that the time is 7:30 is correct, but is it knowledge — or is it more of a lucky guess?

Another thought experiment: Given the following scenario, do I “know” that my wife is in the house? I come home from work and see my wife in the kitchen. As it happens though, what I see in the kitchen is actually a perfectly rendered hologram. My wife is in the house though, but she’s upstairs where I can’t see her. Again, the three JTB conditions are true, but my justification for belief has nothing to do with the truth of the matter.

These types of thought experiments are called Gettier problems, named for Edmund Gettier, who in 1963 published a paper called “Is Justified True Belief Knowledge?”

If this kind of thing is of interest to you, Wikipedia has articles on Edmund Gettier and Gettier problems and the Internet Encyclopedia of Philosophy has a more in-depth treatment.


Watch Out for the Gospel of the Times

14 Apr 2013 /

everything is permitted
absolute freedom of movement
that is, without leaving the cage
2+2 doesn’t make 4:
once it made 4 but
today nothing is known in this regard

— Nicanor Parra, “Watch Out for the Gospel of the Times”


Dare to Be Wise

2 Mar 2013 /

Sapere aude! Have courage to use your own understanding.

— Immanuel Kant

The Best Measure of Truth

21 Nov 2011 /

If you act as if something is true, you will shortly find out whether it is or isn’t. Any reduction of effort or increase of abundance you enjoy as a consequence of your new belief is the best measure of its truth.

— Jim and Michele McCarthy, Software for Your Head

Don’t Know What You Don’t Know

24 May 2011 /

It is essential not to profess to know, or seem to know, or accept that someone else knows, that which is unknown. Almost without exception, the things that end up coming back to haunt you are things you pretended to understand but didn’t early on. At virtually every stage of even the most successful software projects, there are large numbers of very important things that are unknown. It is acceptable, even mandatory, to clearly articulate your ignorance, so that no one misunderstands the corporate state of unknowingness. If you do not disseminate this “lucid ignorance,” disaster will surely befall you.

Lost

Human nature is such that we dislike not knowing things that are important to our well being. Since there is so much we don’t know in a software project, the nearly universal tendency among developers and their managers is to gloss over or even deny altogether the extent of their ignorance. You should reward and treasure those who consistently make themselves aware of the list of relevant things that are currently unknown. It requires mental and psychological strength to resist the normal human cravings for certainty and order. It especially difficult to believe in uncertainty when things have a veneer of orderliness, which is often the case. Pseudo-order is a maladapted defense against uncertainty.

The organization surrounding you will undoubtedly abhor uncertainty, would infinitely prefer pseudo-order and will make countless attempts to magically convert your ignorance to knowledge. Your job is to make uncertainty an unshakable fact, and to coerce the reshaping of the surrounding organization to cope with the uncertain situation. The organization must learn to thrive in an uncertain environment for its own well being.

You should expend a great deal of effort making sure that all the people on the project are aware of their ignorance rather than naively converting it to falsehoods. Bear down on them until they realize they haven’t comprehensively assessed the unknowns. In the successful project, this is much easier in the early stages, or during times of change. This is no time for niceties. People ultimately prefer success even if disillusionment is a prerequisite.

— Jim McCarthy, “21 Rules of Thumb for Shipping Great Software on Time”

I Don’t Think Anybody Knows

11 Dec 2009 /

One of the hardest things to convey to students is how often the answer to a question is, “I don’t know, and I don’t think anybody does know.”


Not Knowing Things

25 Jan 2009 /

But I don’t have to know an answer. I don’t feel frightened by not knowing things, by being lost in the mysterious universe without having any purpose, which is the way it really is, as far as I can tell, possibly. It doesn’t frighten me.