Evidence - an operational definition

[Graeme]

How does evidence operate? Not what is it, but "how," does it occur?

Thought Experiment #1: I have a hypothesis that all cats are black. I do studies on cat populations. I measure and count the numbers of cats in my neighborhood. I make careful tallies of my counts, and I spend time researching the travels and behaviors of the cats. I write papers on my studies and publish them in the esteemed journal, "Feline Dynamics."

One day I come across a strange creature which is the same size, and shape as a cat, meows a lot, licks it's paw and constantly struts around like it owns the place before finding a warm and cozy cushion to fall asleep on. This strange creature has white fur.

I deem it not to be a cat, as according to my hypothesis, all cats are black.

What mistake am I making?

[Graeme]

Further to the above, here is a fellow who is making the same basic error as demonstrated in my black cat hypothesis example.

Concave Earth Theory: http://www.wildheretic.com/concave-ea...

I particularly like his "Is the sun a light bulb?" : http://www.wildheretic.com/is-the-sun...

[Graeme]

Further to the above,

Confirmation Bias: https://en.wikipedia.org/wiki/Confirm...

and a clever resource at Visual Capitalist that brings together the known cognitive biases: http://www.visualcapitalist.com/every...

[Graeme]

"If it disagrees with experiment it's wrong. In that simple statement is the key to science."

Richard Feynman (1964): https://www.youtube.com/watch?v=EYPap...

The bottom line, the best process we have for understanding this universe we find ourselves in is a system for discovering error.

We can be certain about what is demonstrably false, anything else, not so much, and we can only discover if something is false if we are willing to admit what the evidence is.

[Graeme]

So what's my take on 'evidence,' - The normal behavior of human beings is to accept only that 'as evidence,' which already matches to their deeply held beliefs, predispositions, biases and cherished and 'clearly obvious,' truths.

Does anyone know anyone who regular wakes up in the morning and says, "I really hope that one of my cherished beliefs is refuted today."

Or is it far easier to find examples of someone greeting the refutation of a cherished belief with attack, hatred, dismissal, disdain, rejection, or shunning?

[Graeme]

The number one observation I have of the sometimes heated discussions that are held in this group is that the primary cause for the differences of opinion are the different definitions of 'admissible evidence,' for the topic.

And that the differences of 'admissible evidence,' is driven by the above mentioned biases.

People will continue to talk at cross purposes until they are willing to challenge their own definitions of what 'evidence,' is applicable for any conversation.

(Given human nature, the likelihood of that happening is low)

[Nik]

An excellent demonstration and conclusion, Graeme!
Believing in fallacies, when evidence points otherwise is grave.
Sometimes also we make theories, generalizations and stereotypes, where there shouldn't be any.
For example, if I go to France and start talking English to them while they seem to not understand me, I may develop a belief that French don't know English. That may hold until I meet one, who does. Then, I may start to believe that French don't speak English with rare exception. And that until one of those, who previously seemed to not know English, grudgingly answers something in English and mentions that s/he just doesn't like speaking English. So I may have a whole theory here, while it's only statistics about how many do know, who many don't and how many don't like -:)

[Bernard]

Graeme wrote: "How does evidence operate? Not what is it, but "how," does it occur?

Thought Experiment #1: I have a hypothesis that all cats are black. I do studies on cat populations. I measure and count the nu..."

What you are pointing out is probably the most common logical fallacy observed: the syllogism, the other most frequent one being circular reasoning.

[Ian]

The major problem with your cat example is terminology. Classification means that you put those so classified in a set. A set comprises the elements of the set, together with the rule that defines set membership. You started off by defining the set as the set of black cats, but you called it "cats". A white cat does not fit the set of black cats because it violates the rule of set membership (it must be black) but then got into trouble because your set was not properly defined. There is no problem when you properly define what you mean. This sort of problem is a very major one in the life sciences, where they try to classify something into species, genera, families, etc.

[Graeme]

Hi Ian, what you are describing is the ideal world. What I'm trying to illustrate with a simple analogy is the situation where people have a belief system and define the set of evidence to support the belief system.

If we followed Feynman, we would define a refutational event for the "Black Cat Hypothesis," and then go looking for a non-black cat.

My point is, that people normally don't do that. The last thing people want to do is refute their own beliefs.

[Ian]

Hi Graeme, what I was describing was logic. I know people can believe anything. There are some who still seem to think the planet is flat, and we have a President in the US who thinks global warming is a hoax. Actually, as a theoretician myself, I know trying to refute your own conclusions is terribly difficult, but if you want to develop good theories, you have to do it. When you have just developed a new hypothesis it is not so difficult to try to refute it, but once you have held on to it for a year or so, it becomes very difficult. Of course there is the other side of the coin: if you do not hold on to your ideas when they go against the general beliefs, you lack courage and never change anything.

Of course, black cats are less important, so if you wish to believe all cats are black, so be it, but my cat Horatio will be rather upset, being ginger 😄