My mother once had trouble with cramps and back pain for a month, but then I took her to see the Pirates of the Caribbean with Johnny Depp, and the day after, all her problems with pain and cramps were gone!
So clearly, the solution to solve people’s cramps and the current pandemic of back pain is to see more movies with Johnny Depp!
Because it “worked” for her, and it cured her back pain!
The above is an example of erroneous reasoning and low-quality thinking. The faulty reasoning used (called the post hoc error) is why we cannot show what “works” with anecdotes and subjective experiences.
“Establishing the temporal priority of one event over another is not a sufficient condition for inferring a causal relationship between those events. One cannot assume that post hoc ergo propter hoc—that an event that occurs after another event (post hoc) therefore occurs because of that other event (ergo propter hoc). “(Damer 2008)
Additional signs of causation might be a spatial association or a description of regularity. However, chronological priority alone is not enough to confirm a causal relationship. Because if it was, all events that prefaced another event could be assumed to be in a causal relationship with the previous event.
So this is one reason why anecdotes and subjective experiences are not an reasonable and logical proof of causal inference and a causal relationship.
Moreover, this problem is further compounded by the fact that some symptoms and signs (like back pain) get better or cease without any form of treatment. Back pain usually begins to improve after 2-5 days and typically resolves in less than one month (Atlas et al. 2001, Klineberg et al. 2007). Therefore, it is very tough to know if the mere passing of time had its effect or it was a specific effect of the intervention.
Damer E, Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments, Wadsworth Publishing; 6th edition, 2008.
Atlas SJ, Deyo RA. Evaluating and managing acute low back pain in the primary care setting. J Gen Intern Med. 2001 Feb;16(2):120-31.
Klineberg E, Mazanec D, Orr D, Demicco R, Bell G, McLain R. Masquerade: medical causes of back pain. Cleve Clin J Med. 2007 Dec;74(12):905-13.