Wednesday, May 5, 2010

How do we evaluate evidence and belief?




Dave Barry was interviewed in this past Sunday’s New York Times Magazine. In the process, he described his pet peeve:

“One thing that is not in my fridge is ketchup and mustard. You know why? Because you don’t have to put them in the fridge! Too many Americans are putting cold ketchup on nice, hot hamburgers. And I ask those Americans, When you go to the diner, where is the ketchup? Sitting out on the table.”

Now, this made my wife and I laugh because it’s true: we have our condiments in the refrigerator and it never occurred to either of us not to. Yet, Barry is right. We never see ketchup anywhere but on the table at restaurants. We joked about it for a bit, clearly resolved to take them out of the fridge, and then Kim got the bright idea to look at the labels. Lo and behold, each has very explicit instructions to refrigerate after opening.

I would be hesitant to suggest that we were committing the appeal to authority. We weren’t persuaded by the fact that it was Dave Barry who told us to move our ketchup and mustard; we were persuaded by the evidence. His argument is irrefutable. Every day in restaurants millions of people eat ketchup and mustard from the table and they don’t get sick. How can that be wrong? One might argue that restaurant condiments get used much quicker than those at home, and that over the long term it's best to refrigerate them, but this doesn’t seem to be the case. The issue is, it seems like you don’t have to keep them cool at all.

So, there is a philosophical problem here. Not only who do we believe, but how to we evaluate the argument? First, we can’t believe Dave Barry just because he is Dave Barry; that would be appeal to authority. But, we can’t believe the ketchup and mustard people just because they are the ketchup and mustard people. That would be appeal to authority as well. But the ketchup and mustard people presumably have some expertise that makes them more reliable than Dave Barry, so maybe believing them is not the appeal to authority after all. Then again, the evidence that we have – years and years, case after case – verifies that Barry is right. Refrigeration is unnecessary. How do we determine who to believe?

There must be some standard of objectivity to evaluate the evidence, and presumably, that evidence has to be larger than our experience. Is it enough that millions of restaurants continue the practice, or do the tests have to be conducted in a laboratory? And if the latter is true, does this discredit the experience that we each rely on day-to-day?

Obviously, the most basic question is where we should keep our condiments, but the deeper one is how we evaluate the evidence of arguments. What counts as enough to regard a proposition as true? Dave Barry, you opened a Pandora’s box, and I’m not making this up.

Don’t want to comment using Facebook?
Use Blogger to comment instead.

8 comments:

  1. It seems a bit like there is a huge assumption being made that since you never see condiments coming from a refrigerator in a diner, then they are never refrigerated or otherwise maintained.

    I also challenge your claim that Dave Barry is an authority of anything to anyone. Thats just a personal bias for me though...

    Listening to the manufacturers is an appeal to expertise for sure and carries more weight, although a careful reading suggests they are equally concerned with a loss of flavor as the are with spoilage.

    I don't think the tests need to be conducted in a lab, but I do think they have to be run with rigor. i.e. It is probably insufficient to reflect on what one thinks one is experiencing in a diner and draw conclusions from it without further qualification.

    I would like Dave to show the courage of his convictions and store his ketchup out on his deck in open sunlight over the summer and see how it goes...it might not spoil as quickly as milk, but it will spoil...

    ReplyDelete
  2. Chris,

    You said:

    "I also challenge your claim that Dave Barry is an authority of anything to anyone."

    Dave Barry is currently the pre-eminent authority on... Dave Barry. Just sayin.

    ReplyDelete
  3. I've worked in restaurants that keep condiments on the table, and eventually ketchup will spoil and explode on opening, kind of like popping the cork on a bottle of champagne. You can tell it's gone bad when there are visible bubbles. Restaurants usually don't have this problem because the ketchup is used up before the fruit ferments (tomato=fruit, fruit ferments!), and Dave does not have this problem because his cooking is so bad that he uses ketchup on everything.

    ReplyDelete
  4. Just so you all know: we made Dave Barry's Blog!

    http://blogs.herald.com/dave_barrys_blog/2010/05/hmmmmmmmm.html#comments

    Over 300 hits on PQED in the last three hours.

    ReplyDelete
  5. Next time you go grocery shopping, have a look at different brands. Some say "refrigerate after opening" and some don't. I suspect it depends on the ingredients.

    A friend of mine keeps her ketchup in a cabinet and it's quite brown. I wouldn't eat it! But she's in her 80's and it hasn't killed her yet!

    ReplyDelete
  6. This is a much easier question when you prefer your condiments cold anyway.

    ReplyDelete
  7. If ketchup (catsup...another point of controversy) is kept out too long in very warm weather it begins to ferment and ketchup wine doesn't taste very good in my personal opinion. I haven't experienced mustard wine yet. However, when it comes to preference, I would rather room temperature condiments, including barbeque sauce, hot sauce, and steak sauce with the only exception being mayo.

    ReplyDelete
  8. If there is a standard of objectivity in the evaluation of an argument, I think it's mainly the plausible advantages that apply to each side of it. It's funny that you mentioned confirmation bias a few posts ago, because I instantly believed the ketchup and mustard people because I'd always been taught to put the ketchup and mustard in the fridge. Since I believed that way, I held a bias. And, I've never gotten sick from eating it out of the fridge, illustrating a plausible, pragmatic advantage.

    ReplyDelete