If a tree falls in the forest, does it make a sound? Does that depend upon someone being there to hear? That is a classic example of the mixup of two distinct ideas — the idea of an observable, and the idea of an observation.

First of all — consider a specific tree — you know, that shagbark hickory with the funny bend in its trunk, the one near the path. Is that tree standing? Cannot say. It was there yesterday afternoon, but no-one has gone to check since then, and we do not have a TV camera watching the tree. Even if we did have such a camera watching the tree, we could not say if the tree is standing NOW — only that it was standing a second ago, whatever is the lag time between the camera’s recording and the image rebroadcast and viewing by us.

Still, no doubt, whether the tree (that particular hickory) is standing, is an observable — ie capable of being observed at various times. At certain times in the past, the tree may have been observed — via a person or via proxy, eg a TV camera/recorder. Those are observations. One observable, and several observations, at specific times, or possibly no observations. Most of the time no observations, though. We do not watch the tree all the time. We’re not likely to misplace the tree, to confuse it with another tree. But what about the may apple plant at its base? Which one of the hundreds of may apple plants are we talking about? The one with a single leaf? Or the one with a pair of leaves? Or were those two observations actually of the same may apple plant, at different stages of its growth? Observing a living creature, plant or animal, is as unrepeatable as stepping into the same river twice.

All this is preliminary, just to get some distinctions in mind. I have minimal training in philosophy, and there are subtle distinctions that escape me. But I can at least know that we are at risk of serious confusion if we make no distinction between an observable (capable of being observed), and an observation (time-specific event of data gathering).

Is the moon there even if we are not looking at it? Yes, I would say so — the moon is an observable, even if we do not make an observation. Was the moon there a million years ago, when we were not around to observe it? Yes, it was an observable. Sometimes nature will deliver us a delayed observation. That lunar meteorite which I spoke of several weeks ago, was an observation — I observed the meteorite quite recently, but the sample of lunar rock which was propelled into space by an asteroid impact, was a sample taken between last month and perhaps a billion years prior to last month. That meteorite, with some dating work, is late-arriving evidence that the moon was there a long time ago, before there were people around to observe it.

Best wishes,
Ken Roberts
05-March-2014