> What intuition should a layperson have to suggest that obviously opacity/transmissivity is multiplicative? Tinted windows and sunglasses come to mind. Intuit

> What intuition should a layperson have to suggest that obviously opacity/transmissivity is multiplicative? Tinted windows and sunglasses come to mind. Intuitively, if you put translucent things back to back, you expect light to still pass through, albeit less of it, but always some. A noteworthy exception is when using polarized filters, which can unintuitively block out 100% of light depending on the angle between the filters.