Why is probably the toughest of the interrogatives, the five W's and the one H. It asks for the cause and causes are tricky.
We learned in statistics that "correlation is not causation", meaning events that happen with other events may not be their cause. Every time my fork is raised to my mouth bearing food, my mouth opens but the nearness of the fork to my mouth does not cause it to open. Finding causes assists in our efforts to understand and control our world. Who wants to control their world? Nearly everyone at times. When I discover I have measles, I would like to discover the cause of getting the disease so I can avoid getting it again and your getting it.
I think it is funny how I decided I liked experimentation as a young man and figuring out the world as it actually works but I never noticed the role of memory and history in that process. If we don't know what steps were taken in the experiment and how the sample being used was found and experimented on, we can't do much with the experiment.
In grad school, I was ok with taking a course in the history of psychology but I had no expectation that the course would be a valuable as it was. The text we used in that class, "The History of Experimental Psychology" by Edward Boring (I kid you not) got me thinking about causes and causation. The text asked "Why is this apple tree growing here?" Answers: because Grandpa planted it there but also because it got adequate sun and rain and also because no large animal grazed on it or stepped on it and because no plant virus or fungus infected it.
A technique to stimulate good thinking about a phenomenon is the use of five Why's.
Why did my mom date my dad? Because my parents were attracted to each other.
Why were they attracted to each other? Because both had good shapes and high levels of hormones.
Why did they have good shapes and high hormone levels? Because they had good nutrition and were the right age for sex hormones.
Why did they have good nutrition and the right age?
Sometimes, like parents beleaguered by a three year old who has gotten into the why-why-why game, we stop without getting to #5 but sometimes the answers are indeed helpful and move our thinking to new areas for thought and investigation.