Absence Of Evidence Is Not Evidence Of Absence?

Evidence Of Absence?
Evidence Of Absence?

Several famous people have used this phrase in lots of situations. Recently, Neil deGrasse Tyson used it in the following way : “One of our mantras in science is that the absence of evidence is not the same as evidence of absence.”  This outburst was in defense of a failure of his memory in quoting George W Bush. Tyson got it wrong and after some embarrassing back and forth, finally admitted his error.

In thinking about the meaning of the phrase I realized that the phrase can be nuanced to death. You could spin the phrase to mean pretty much anything.

So, how do you take the meaning?

  • Evidence is evidence, and if there is no evidence to support a theory, there is no evidence. You cannot say that the absence of evidence proves the theory is false. You can only speak of things in the language of uncertainty, i.e., the theory is likely false if there is no empirical evidence to the contrary.
  • If there is no elephant in the room, and if you don’t see any evidence there is an elephant in the room, this lack of evidence means there is no elephant in the room. So, a lack of evidence can be used as evidence of absence.
  • That there is no physical evidence of mental telepathy means that mental telepathy does not exist.
  • There is no evidence mental telepathy does not exist, therefore it exists. This is called an Argument from Ignorance.

Tyson said that the phrase was a scientific mantra. Why would he say that? Maybe his mantra is really, “Everything I say is correct and shame on you for questioning my veracity.”

Everything depends on evidence. In science evidence must be data indicating actual physical parameters. Evidence is measured, counted, photographed, etc.

Of course, there are the ever popular examples as follow:

  1. If a tree falls in the forest and there is no one to hear it, did it make a sound?
  2. If your wife talks to you during a football game, does this mean you are hard of hearing just because you didn’t hear her?

I am guilty of getting into some deep, unfamiliar waters here. This stuff probably comes under the heading of philosophy. I skillfully endeavored to not take philosophy in college. I was more interested in electrons and women, not necessarily in that order.

It is time to stop this article. I have a headache.

8 thoughts on “Absence Of Evidence Is Not Evidence Of Absence?”

  1. Good point, Ed. If there is no evidence of God, that is not evidence of his absence. The evidence may be there, but most people don’t know where to look for that evidence. On the other hand, because there is no evidence that something does NOT exist does not mean that it exists. I think I am getting another headache.

  2. well, you can’t imagine what a huge smile i got on MY face when, as I read, knowing I was going to write “you gave me a headache,” I then stumbled upon your last sentence!! HA! Oh, just read your comment and you have even MORE of a headache!
    I’d better stop reading…I’m susceptible!!

    interesting piece, however…and I DO think this is all about “whatever I SAY is right” by that dope in the image!

  3. As usual, Z, you are correct. It is amazing how we spin and twist the English language to make sure we are always right.

  4. and kind of scary, but not AS scary as the torture report Democrats are allowing to come out Tuesday; a report whose sharing with the public/world is forcing the military to tell their embassies and bases to be on the lookout BIG TIME. And still the Dems are releasing this, have you heard?
    Not sure if this is to smoke screen Gruber’s hearing……….but if Obama thinks having Gruber’s testimony overshadowed by the BIG media flap this torture report’s going to get (so the public doesn’t catch on about Obama’s pet health care project,) and putting US in REAL THREAT instead, that’s astonishing even for HIM, the rat.

  5. I don’t’ think there is another explanation for the Dems releasing the one sided report. It is designed to keep the heat off Obama Care.

  6. I remember Tyson being one of the main proponents to reclassify Pluto as not being a planet. First off, who cares? Secondly, it’s round and has at least a couple moons. We’ll know more when New Horizon’s arrives on site. Tyson is a big fan of Sagan who was an Atheist(wonder if he still is), and then Tyson seems to be really afraid of black holes. I’m not afraid of black holes at all. I never expect to meet one and if I do, the journey will be worth it I suspect. I’m not sure Tyson is very logical or that he spends his thinking time wisely.

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