Glenn A Knight

Glenn A Knight
In my study

Thursday, July 31, 2008

The Absence of Evidence

Donald Rumsfeld made famous the saying that the absence of evidence is not evidence of absence. I don’t know anything about the origins of the saying, though I gather it was not original with Rumsfeld. The dictum itself may be unobjectionable, but Rumsfeld used it improperly and may have misled people thereby as to the meaning, and the limits, of this principle. I will explore here what the absence of evidence means.

The Absence of Elephants

You’re sitting at home on a Sunday afternoon, watching golf on television, which is to say that you are half-asleep, when the phone rings. The caller is one of your neighbors, and he says that there is an elephant in your front yard. You go to the window, you look out on the front yard, and there is no elephant there. You go back to the phone and say to your neighbor, “Good one. You made me look.” Then you hang up and go back to your golf.

I can divide your knowledge about elephants in your front yard into three states. In the first place, before the phone rings, you have no information. There is an absence of any evidence, as far as you know, regarding the presence or absence of elephants in your front yard. In fact, the possibility hasn’t even been raised. (It may be a general rule that a genuine absence of evidence coincides with a lack of interest in the question at hand.)

In the second state, after your neighbor calls, you have one piece of evidence: your neighbor’s testimony that an elephant is in your front yard. This may or may not seem likely to you, depending upon where you live and your prior experience. Under the principle of induction, if there has never been an elephant in your front yard before, it may seem unlikely that there is one at this time. However, the inductive problem, which indicates that any inductive conclusion can be overthrown by a single contrary example, implies that one should always be aware of the possibility of an instance contrary to one’s prior experience. One might call this keeping an “open mind.” Therefore, you go to the trouble of looking at the front yard, rather than dismissing your neighbor’s statement as a lame joke.

Finally, after you have looked at the front yard, you have another piece of evidence: your visual inspection of the yard shows that there are no elephants there. This evidence contradicts your neighbor’s statement, and (in your opinion) is conclusive. If you don’t see an elephant, there isn’t one. Your conclusion is that there is no elephant in your front yard.What I want to make clear with this example is that the absence of an elephant is not an absence of evidence concerning elephants. You have evidence concerning elephants, and this evidence is negative. That is, you have evidence of the absence of elephants. More generally, the absence of a phenomenon is not the same as the absence of evidence relevant to the existence of that phenomenon. Negative evidence is not the same as the absence of evidence.

The Case of Iraq’s Weapon’s Programs

Where Mr. Rumsfeld went wrong was in identifying an absence of material showing a particular outcome with an absence of evidence about that outcome. In fact, due to United Nations’ inspections, U.S. intelligence, and Iraqi reports, there was a lot of evidence about weapons of mass destruction in Iraq. On the one side, you had statements from Saddam Hussein and some of his underlings affirming that some weapons programs were in operation. (Whether they believed their own statements, or were running a bluff, is still uncertain.) On the other side, you had on-site inspections of places where such activities had taken place in the past, as well as places identified as suspicious by intelligence agencies, all of which showed that Iraq had complied with orders to terminate these programs.

In other words, the “elephant” in this case were weapons of mass destruction (WMD), and programs to manufacture and distribute them. Saddam Hussein himself, and certain intelligence sources claimed that there were active WMD in Iraq. On-site inspection, documentation, and a variety of intelligence sources contradicted those claims. Some photographic intelligence, much of which was (and always is) inherently ambiguous, supported the affirmative case. Other evidence supported the negative.

However you might wish to characterize the situation in Iraq in 2002 and 2003, an absence of evidence was not the problem. The problem was that the evidence available did not all point in one direction. It was not dispositive. It was clear that some of the weapons programs that had been in operation prior to 1991 were no longer functioning, at least not at the same scale or in the same places as they had been. It was clear that a lot of material had been destroyed under the sanctions regime, while there were no findings to show that it had been replaced. It also appeared that Saddam Hussein had the intention, or at least the wish, to develop WMD, if he ever had a free hand to do so.

In the end, by deciding to justify the invasion of Iraq on the existence of WMD, the Bush administration asserted that the affirmative evidence was more compelling than the negative evidence. A lot of people think they were wrong. To the extent that they dismissed the negative evidence as “an absence of evidence,” they were certainly wrong.


The absence of evidence means that one has no information about a subject. The absence of proof that something exists is not the same thing as the absence of evidence regarding its existence. Once one has evidence, one must evaluate it. Often, one needs to seek additional information to determine whether the initial evidence is credible or not. In many cases, the evidence is ambiguous or contradictory. Frequently, as in Iraq, the problem is not an absence of evidence: it is an inability rightly to assess the evidence one has.

Sunday, July 27, 2008

Pacific Northwest Trip Report - Part II

Helen and I spend July 2-5 in Spokane, Washington, along the Spokane River. We drove to East Wenatchee on the 5th and stayed overnight with friends. We went on to Tacoma on the July 6, where we visited Mike and Linda Sawers, our cousins. On the 7th we went on the Harstine Island, in Puget Sound, with a stop at Olympia to see Allan and Jeanne Vogel. We stayed in Harstine for several days before heading back to Colorado Springs on the 10th.

We spent the 2nd, 3rd, and 4th with my younger sister Linda and her husband, Fred Anderson, in Spokane. We arrived on the 2nd at about 10:00 AM, having driven in from Moses Lake, just in time to watch Linda run off with our niece, Lindsey Knight. Lindsey was on her way to a soccer camp, so Helen and I made ourselves at home in Linda’s condo while we waited for her return. The three of us went to a nice restaurant – C.I. Shenanigans – in downtown Spokane, in between driving Lindsey from one appointment to another. In the late afternoon, Fred came home from his job in Newport, and Lindsey and her mother, Kris, came to dinner with us. We had a good time getting reacquainted. Fred Anderson may be new as a member of the family, but I've known him since we were both about 12, the age Lindsey is now.

On the 3rd we wandered around Brown’s Addition, which is undergoing a lot of renovation and building, after some years of decline. We found a really good restaurant just up the hill from the condo, Marron. A nice touch, I thought, was that the wall on the street side was made of two automatic garage doors, so that they could open up the walls on a warm evening.

My other sister Nancy and her partner Joel Neier came over on the 4th - they were going to a wedding on the 5th. My brother Bill flew in from Eugene, Oregon on the 4th; he'd been undergoing some training for his new job down there. Some of us wandered around the riverside during the day, admiring the falls, and in the evening we gathered at Linda and Fred’s to watch the downtown fireworks show. We met two of Linda's nieces and her grandnephew, Braden. Braden is four, and he's very cute. The weather had been pretty warm in the first part of the week, but it cooled off nicely for the 4th. On the 5th, most of us met at Huckleberry’s for breakfast, and then went our separate ways. Linda and Fred took Helen and me on a guided tour of the South Hill of Spokane, an area I hadn’t been to in years. The Park Inn tavern is still there.
Because the weather had cooled off some, we drove to East Wenatchee by way of Coulee Dam, and managed to find my uncle's old house in Elmer City. We drove on Tilmus Street, in Coulee Dam, where I lived when I was four or five, but I didn't remember the house number. There is some amazing scenery in that area. You go from high desert, to flood-sculpted volcanic towers and canyons, to irrigated fields of wheat and corn. When we dropped down to the Columbia River valley around Orondo, we were in the orchards of apples, peaches, cherries, apricots, and all kinds of fruit. The orchards in the desert always remind me of the Euphrates River in Turkey, on the way up to Malatya.

We stayed over with our friends Lloyd and LaVerne Smith in East Wenatchee. The weather was moderate for a change - highs in the mid-80s, instead of the high 90s or 100s. Then we drove down to Tacoma and saw my cousin Mike and his wife, Linda. As it happened, we arrived on July 6, which was their anniversary. It had slipped my mind that we were arriving on that date, but we had a good time reminiscing about their wedding. It was about 108 in Yakima back on July 6, 1968, and it must have been 130 inside the church. It was much nicer in Tacoma in 2008. We went downtown to the harbor, Mike and Linda took us to a great seafood place for dinner, and we got to enjoy their house. They have a great view of Puget Sound, all the way up to Mt. Baker (on a clear day). We spent a few days at Nancy's place on Harstine Island, stopping for lunch with our friends Al and Jeanne Vogel on the way. We were privileged to visit the Vogel’s boat, Celt’s Cupcake, at its marina in Olympia. Harstine is quite a large island, with a number of spellings available for its name. We walked on the beach and along the wooded roads, and we made good use of the pool. One day we went to Belfair to visit the Theler bird refuge. This consists of boardwalks over both fresh- and saltwater marshes along Hood Canal, and was a very nice contrast to our birding haunts in Colorado. We went into the local metropolis – Shelton, for dinner one night, and had the misfortune to dine at the Ming Tree. This was quite possibly the worst Chinese food I’ve ever eaten. After three enjoyable days in the water world of Puget Sound, we had to leave.

Then we drove home - over 1,500 miles in three days. We took US-12 from Chehalis to Yakima, so we had views – not close views, but sightings, of Mt. St. Helens, Mt. Rainier, and Mt. Adams. We re-crossed the Colorado line south of Laramie Saturday afternoon, July 12, and made it home in time to feed our cat Hobbes his dinner. It’s good to be home.

Saturday, July 26, 2008

Pacific Northwest Trip Report - Part I

Colorado Springs to Spokane

We traveled through the northern Rocky Mountain States to the Pacific Northwest to see friends and relatives, to try camping out, to see some lovely scenery, and to get out of the too-familiar surroundings of home and work in Colorado. We left Colorado Springs on Saturday, June 28, and returned on Saturday, July 12, after 15 days, 14 nights, 3625 miles, and many gallons of gas. I worked out the costs and mileage from the last fill-up before the trip through fueling and washing the car on July 13. 3653 miles took 120.6 gallons of gasoline, at an average price of $4.17 per gallon, for a total cost of $502.91. The Subaru managed 30.29 miles per gallon on the trip.

The first day, June 28th, we drove only as far as Ft. Collins, Colorado. We had decided to make the first day a short one, in order to avoid rush-rush packing and last minute panics. The tactic worked well, and we had a pleasant morning packing the car and driving up I-25 to Fort Fun. We got to the Kiva Inn in Ft. Collins just in time, as it happened. There was a bike race for charity going on, and we got the last available room in the motel. We had lunch at one of our favorite sports bars, C. B. & Potts, and dined vegetarian at The Rainbow. On all of our trips to Fort Collins, we hadn’t ever tried The Rainbow, and it turned out to be excellent.

On the 29th, our 34th wedding anniversary, we drove out of Ft. Collins and took US-287 to Laramie. This was a pleasant drive, through rolling hills, some of them quite large, and with interesting scenery. The time one loses by taking the slower road is recovered by cutting off two sides of the triangle: Ft. Collins-Cheyenne-Laramie. We got on I-80 in Laramie and drove, drove, drove. We made it into Utah, and camped out at Willard Bay State Park, on the Great Salt Lake. We had not tried camping in a number of years, but we found a nice site, set up our tent, walked around checking out the birds, and quite enjoyed ourselves. We benefited from camping on a Sunday night; there were only two other groups in the campground.

On Monday, the 30th, we toured the Bear River Migratory Bird Refuge at the north end of the Great Salt Lake. The refuge was very well set up, especially considering that they were still recovering from the disastrous flood in 1983. The refuge caters to freshwater birds, and is separated from the Salt Lake by low dikes and causeways. In 1983 the lake overwhelmed the dikes, destroyed the visitor center and other buildings, and wrecked the roads. More importantly, the salt water ruined the environment for the sort of birds that had been using the refuge. They have done a lot of work, and the proof of their success is in the results. We saw Yellow-Headed Blackbirds, American Avocets, Black-Necked Stilts, and many White-Faced Ibises. There were also both Clark’s and Western Grebes. Our tour of the refuge took some time, so we only made it to Boise that night. After staying in a motel in Boise, Idaho, on the 30th, we drove across the Western half of Oregon the next day.

The Oregon Trail Interpretive Center in Baker City, Oregon, is well worth a visit. We enjoyed the exhibits and found some postcards to send to friends and family. Otherwise, the trip through Oregon involves impressive scenery, alternating fertile valleys with impressive mountains, and a lack of decent places to eat. We finally found a Denny’s in Kennewick, Washington, for our belated lunch. From Kennewick we headed north toward Spokane, but turned off at Mesa and drove through Othello and the Columbia River Wildlife Refuge to Potholes State Park.

We camped there on the first of July. Potholes State Park in central Washington state is pretty cool: 120 campsites, a huge reservoir, lots of Ring-Billed Gulls, and interesting scenery shaped by lava flows and glacial floods. The park is named for the many depressions full of water, formed when the water table rose in an area of sand dunes. The Drumheller Channels, formed by the Spokane Floods which punctuated the last series of glaciations, contain dozens of these small lakes, each a little watery habitat in the desert. We enjoyed the camping at Potholes; each campsite was set off from the others by a ring of poplars, and there was a large (irrigated) grassy area where gulls and soccer players congregated.

On July 2nd we drove from Potholes State Park, by way of Moses Lake, to Spokane, the first destination point of our trip. Although we did some birding en route, I probably read more in Roadside Geology of Washington than in Sibley’s, and I didn’t bother to take formal notes of every swallow or House Sparrow we saw. It’s a long drive, and it took us into a fifth day of driving. We had left Colorado Springs about 10:00 AM on the 28th of June, and we arrived in Spokane at 10:00 AM on the 2nd of July.

Monday, July 21, 2008

Justice and Religion

There’s a fine old country gospel song, “Farther Along,” I can recommend to any of you who are fans of hillbilly music. It’s been recorded by a number of people, including Dolly Parton, Emmylou Harris, and Linda Ronstadt on their Trio album. Look it up sometime.

The song has a question and answer structure. A typical verse runs:

When death has come and taken our loved ones,
Leaving our homes so lone and so drear;
Then do we wonder why others prosper,
Living as sinners year after year.

The answer is, of course, that “farther along” we’ll understand why the world works in this apparently unjust way.

This is just one expression of a question central to all religions. If the universe or its God is just, why do bad things happen to good people? And why, on the other hand, do good things happen to bad people? The answer is, of course, that the injustice is only apparent, because it will be rectified in another life. You may suffer in this world, but you will be rewarded in Heaven. The bad man may seem to prosper now, but he will end up in Hell, suffering the pangs of eternal damnation. (Or, in the Hindu framework of reincarnation, the good man will come back in a better situation in his next life, while the bad man will come back as a cockroach.)

We see this theme in Plato’s Republic, which may contain the first really clear expression of the afterworld as an instrument of justice. (Compare The Odyssey, in which the spirits of the dead wander aimlessly in the underworld, their past lives having no apparent influence upon their present circumstances. I might note that, as far as I can tell from limited reading, the Jewish concept of Sheol is closer to the underworld of Odyssey than to Christian images of the afterworld.) We see it in a very strong form in Christianity in the expression: “But many who are first will be last, and the last first.” (Mark 10:31)

The concept of a retributive afterlife seems to arise from the need to reconcile evident present injustice with a basic intuition that life should be fair. There is, in fact, no evidence whatever that the books are, in fact, balanced on “the other side of the river.” But this belief appears to help people to tolerate their otherwise intolerable lives. Some people think that this is one of the most pernicious aspects of religion, in that it leads people to tolerate misery and oppression, instead of rising up to seize a better life. There’s a folk song on that theme too, “The Preacher and the Slave,” by Joe Hill, the chorus of which is:

You will eat, by and by,
In that glorious land above the sky,
(Way up high),
Work and pray,
Live on hay,
You’ll get pie in the sky when you die,
(That’s a lie!)

Joe Hill may have been a little harsh; as a Marxist, he presumably thought of religion as the opiate of the people. Since it is quite evident that life isn’t fair, and since no religious organization I know of can guarantee to make life fair in this world, they are forced into promising justice in the world to come. So the churches won’t be held accountable now for the failings of society, but everyone will be held accountable in the world to come.

Take what comfort you can from that idea. Personally, I’ll just go with “Life isn’t fair.”