So, what's pollution?

We think -- mostly -- in terms of words. So defining the words properly is important.

Take pollution. We talk about it a lot, but seldom think about exactly what it is.

It's easy enough: pollution is an unwanted by-product of a process.

"Unwanted" is the key word. I like curries. My wife doesn't. When I make a curry, the odor is pleasant to me, and not to her. To her the smell is pollution.

As with "weeds." A weed is an unwanted plant. It's a definition strictly in the eyes of the observer.

A rose -- under the wrong circumstance -- could be a weed. And a dandelion could be not a weed. Under the right circumstances.

Same with "noise." Noise is unwanted sound. And actually, it's an unusual word, one that strictly speaking doesn't have an opposite. A classic joke is made of a parent telling a teen, "That's not music, that's noise." So the opposite of noise could be music. Or a baby crying. Or a dog barking.

(The term "noise pollution" is really a redundancy: all noise is pollution).

The point I'm making is that there are a lot of things that are objective. But there are lots of things that aren't. Knowing the difference between things that are inherently objective and things that are inherently subjective is important. Because otherwise our discussions can be speaking past one another.