It turns out that the dress in the photo has been identified, so evidence that will settle the question exists. However, while one is aware of the genuine disagreement and before one is aware of what that definitive evidence shows, we can and should ask the following questions:
- Are those who see gold/white stripes rational in continuing to believe that the stripes are gold/white?
- Are those who see black/blue stripes rational in continuing to believe that the stripes are black/blue?
- Or should both camps suspend belief and conclude that there is something fishy about this situation - something that's preventing either group from rationally forming a belief about the actual colors of the stripes?
It seems to me that just as the disagreeing clocks in my previous post prevent rational belief regarding the actual time, so does the disagreement that captivated the world-wide-web prevent rational belief regarding the actual colors of the stripes on the dress. Until further evidence is available to settle the question, anybody who insists that the dress stripes actually are as they appear to them in the face of that disagreement is just special pleading.
The definition of arrogance is displaying a sense of superiority, self-importance, or entitlement. Without a reason for one group to think that their perception of the dress colors is more likely to be correct than the other, any member of each group who is aware of the genuine disagreement that exists, yet who insists that the colors actually are as they appear, is being arrogant. The humble thing to do here is the epistemically right thing to do, and that is to recognize that one simply can't rationally believe that the dress colors are as they appear. Not, at least, until further evidence settles the issue. The rational thing to do here is to remain agnostic on the question, despite the deliverance of your senses.
Let me explain. Assent to a belief is only rational when it is more likely that the belief is true than false. Since there is no reason to think that one group is more likely than the other to have true beliefs about the dress stripes, the principle of insufficient reason (also known as the principle of indifference) suggests that the probability that either group is correct is no better than 0.5 (after all, both groups could be wrong). Accordingly, the genuine disagreement in this case prevents rational belief. Again, the rational thing to do is to remain agnostic about the dress. One could humbly say that one's best guess is that the colors are as they appear to them, but one would not be rational to say that they believe that the dress colors actually are as they appear.
What if someone perceiving the colors as white/gold were to think to themselves something like this: "Maybe those people seeing black/blue stripes have something wrong with their visual systems? Maybe they are falling prey to an illusion? Accordingly, I can rationally continue to believe that I'm right and they are wrong." Would this kind of argumentation provide a good reason for rationally maintaining the belief that the dress colors actually are white/gold?
Well, if those seeing black/blue stripes are falling prey to a visual illusion, then those seeing white/gold stripes are rational to continue to hold their belief that the stripes are white/gold, but the disagreement calls that very conditional into question! Assuming that the other group is the one falling prey to a visual illusion is a classic case of begging the question (also known as circular reasoning). To avoid this fallacy, one would have to not be assuming that the other group is likely to be wrong; that is, one would need to have reason(s) independent of the disagreement itself to believe that the other group is likely to be wrong.
I've now considered two instances of disagreement: (a) quartz clocks displaying different times, and (b) two large groups of people disagreeing about the colors of a dress in a photo. In both instances, there was no good reason to think that one clock, or one group, was more likely to be correct than the other, and in both instances, assent to belief was irrational, or so I have argued.
Next time, I'll try to summarize what I think are the logical principles involved in considering how disagreement should affect the rationality of one's belief(s). This is the time to chime in if you think that I've made some mistake in my reasoning so far. This is your time to disagree.
By the way, here's a picture of the actual dress in the photo: