Truth and Evidence October 22, 2008Posted by caseyww in Essays, Uncategorized.
This week I’d like to dwell just a little longer on this topic of skepticism and adequate evidence. I know, nothing like beating a dead horse right? Well, there are a couple of reasons I think it will be valuable to linger here just a little longer.
First, there were some great ideas and questions posed in the comments section of the last post that I would like to highlight/summarize. Second, I realize I haven’t quite answered the question of what constitutes “adequate evidence” myself even though I was cracking the whip for everyone else to answer. Mush skeptics, MUSH!
We ended the last post with my somewhat optimistic call for a consensus on what constitutes ‘adequate evidence’ for belief.
Like W. standing on the USS Abraham Lincoln I’d like to declare “Mission Accomplished!” Okay, grant me a bit of sarcastic irony now and then. While, we didn’t quite get to a unified consensus on the requirements for evidence I do think we made some great strides towards defining the issue better.
One issue that kept resurfacing was that people were very apprehensive about defining a ‘single standard’ for what constitutes adequate evidence for belief. On this we seemed to agree: Truth just seems too slippery to nail down with one kind of evidence for all time. One idea raised was that maybe there are different types of truth which each carry their own standard for what constitutes good evidence.
By my count there were 4 classes of truth posed. I’ve taken the liberty to apply some titles:
- Objective Facts
- Subjective Experience
- Cultural Truth
- Untestable Truth
Each class of truth seems to require a somewhat unique approach to belief and evidence. Let’s explore what makes them different in the context of a thought experiment yours truly shared: the color red.
Objective facts are the kind of truth that most of us associate with scientific inquiry. One commenter referred to this class as “concrete phenomena.” I would expand that to include any claim that has physical effects and is falsifiable.* In the context of red we can speak of a particular wavelength of light on the electromagnetic spectrum.
If I claimed objects that are red emit electromagnetic radiation with a wavelength of about 650nm, what would adequate evidence for belief in this statement be?
Well, for most of us a quick visit to Wikipedia or a physics book would be enough evidence to satisfy us that this claim is true. Pretty easy, huh? We often rely on a specific type of evidence that I would call a consensus of scientific authority. This is important because not all of us can be experts on every topic that requires a verdict and it’s certainly appropriate to know when to trust those who are.
(A brief note here: blindly following authority can be dangerous which is why I included the operative word consensus. Science operates on healthy debate which generally moves toward consensus. Yes, rarely there is an Einstein or Galileo who comes along and revolutionizes scientific understanding but generally the fact that one PHD is willing to deny the effects of global warming is certainly is not adequate evidence to doubt its effects in the face of the rest of the scientific community.)
The critical characteristic of objective facts is that if anyone of us wanted to verify a truth before investing in belief we could personally test for evidence ourselves. But how do we make sure the evidence we are getting from our test is good or adequate evidence? We might institute simple rules like:
- Good evidence stays consistent even when we run the test over and over again.
- Good evidence stays consistent even when a different person altogether runs our test.
- Good evidence stays consistent even when the variables of our test are changed (A simple example of a variable would be whether we ran our test in San Diego or Moscow.)
- Good evidence would probably fit in the framework of already established science. (Admittedly this isn’t always the case. But if our test found evidence that overturns whole areas of expert understanding we had better be sure the evidence is ironclad.)
- Good evidence would be able to withstand others trying their hardest to disprove it.
The subjective experience of red is the human sensation of warmth, vibrancy or anger that each of us has in response to the color. We turn a frequency of light into actual experience. Admittedly, this type of truth is a bit harder to nail down than the objective fact of red photons.
Can we really prove that each of us is seeing the same color when looking at red objects? Probably not. However, that doesn’t mean that we can’t determine an adequate level of evidence that would allow us to infer an operational truth.
We may point to the evidence that the vast majority of humans think the color of oak leaves in fall is strikingly similar to the color of a stop sign. We could also include the evidence that from human to human there is negligible difference in the way our eyes and brains are wired. It is certainly reasonable to infer here that we all see red similarly. Even for the colorblind man who may not be able to share this experience the evidence reported to him by the rest of us should be sufficient for belief in the color red.
Another quick note: A couple of commenters asked about the adequate evidence I would seek when trying to ‘prove’ the quality of my decision to marry my wife. I would class marriage as a subjective experience type of truth (maybe even a cultural truth, see below) for which I cannot ‘prove’ truth. However, the affection, commitment, interest and generosity Jess showed me is certainly still evidence which I observed and deemed adequate to invest in the belief that she in fact loved me and would make a great partner.
Just because truth as subjective experience may not be ultimately provable doesn’t mean we shouldn’t be asking for adequate evidence from which we can infer an operational truth for a situation.
We could ask the question, “Do you believe it is good to paint your child’s nursery red?” The answer to this question is a matter of belief in a cultural truth that is fairly fluid and open to a diversity of opinions. In western cultures I think we would usually answer that no, blue and pastels are better for babies. But we can’t necessarily say why and we would be hard pressed to ever prove this point.
Evidence for beliefs in cultural truths does exist but it’s extremely transitory and open for debate. I would imagine evidence here could include studies of the effects of room color on child temperament or imagination or development, but still the moral question of what is ‘good’ temperament or ‘good’ development would still remain.
That being said there is an operational truth that cultures tend to agree on so evidence must exist which points in the direction of truth. Even though it may not be conclusive, evidence can still be deemed adequate after the moral component of these types of questions have been vetted.
I would define untestable truths as those questions that we can conceive of but for which we currently do not have (or can never have) any evidence to help guide our belief. Admittedly, it’s tough to stretch my red example this far but here is my best shot. Examples of untestable truth would be something like:
Our entire universe is simply an elementary particle in an atom on a very large red apple. (Evidence can’t be gathered from outside our universe by definition.)
Flying red elves smart enough to evade all scientific detection control the weather and punish the Pacific Northeast with too much rain because they hate grunge music. (What sounds like an absurd statement, yes, but if the elves can avoid all detection then we can’t really disprove it, can we?)
There were exactly 34 species of red striped dinosaurs. (Not an absurd statement but effectively all the evidence has been destroyed.)
Many commenters asserted that belief was a matter of “personal desire”. If there is a place for personal desire in determining truth and belief this is certainly it. However, ideally I would argue we should remain agnostic (ie. indifferent) to propositions for which can have no evidence. That is I think the appropriate response to mystery is, “I don’t know.”
However, probability and our ability to reason do play an important role here in that we can functionally rule out some untestable claims. Example: There are simpler explanations for weather patterns which science uses to tackle observed phenomena naturally without invoking the existence of flying red elves. Can I prove to you they don’t exist? Nope. However, is it probable and reasonable for me to assume flying red elves don’t exist? I believe so.
*(text amended per comment #7 and #8 below)