More Than Words For Snow #6: Analog is a Perceptual Property

I unfortunately don't have time to write this up more than briefly, so I'll get straight to the point: when we call some property, such as the level of mercury on a thermometer, analog, what we are really expressing is that it's level can change in increments smaller than we can perceive. As far as I know, the level of mercury in a thermometer must ultimately only be able to express the current temperature descretely, since below a certain gradation-size accuracy would be lost out to the random nature of the jostling which is causing the mercury to rise in the first place. That is, below a certain gradiation-size the fluctuations in the level of the mercury would be due to the random directions of the movements in the jostling of the atoms rather than changes in the degree of excitement in the jostling. The thermometer seems to be analog because it seems to change in a smooth fashion, with no visible gradiation. Similarly, many things that seem analog are in fact fundamentally descrete -- record groves, film etc.