Re: How come EVERYTHING isn't what it seems?
Thanks for the comments! I agree that I would call myself a generalist, but more through circumstance than anything else. I never did work out what I wanted to be when I grew up so I ended up spending 40 years in the Australian Public Service, for the simple reason that I scored a job there when I left school and never got around to leaving. 40 years later I am retired and have a bit of time to investigate things, which is nice. In hindsight, I should have specialised in some sort of field of research, I suspect. Originally I imagined I'd be an astronomer as that stuff really hooked me in, but it just never happened. Probably not smart enough anyway!
Still, over the years I have made the time to chase down those things that interested me and I've read a few books and so on, so most of the time I come to a sound understanding at a relatively superficial level. I guess too as time passed I realised I was far more intrigued by the brain, its function and operation, and consciousness, which is what I am right into at the moment. I've managed a little introductory level learning, but I would put my knowledge level at "interested beginner".
Thanks Dave_O for your comments about my set of questions. Those were selected to illustrate the range of apparently simple things that are easily understood at a superficial level, but which on investigation escalate rapidly! The dinosaur one came to me years ago and I've never actually sat down to figure it out. Air pressure led to a protracted discussion on another forum which I think clarified things for me but I am left with a nagging uncertainty. Colour I have a good handle on, but what staggers me about that is that it doesn't exist. The sentence thing I've read up on a bit but never found any mention of what was immediately apparent to me, but that's probably because I haven't really spent enough time on it.
Just for fun, here are the things that really hooked me in for each of those, and why I consider them great examples of things that made me go hmmm...
Sauropods are very very large, especially the really big ones. Yet many of them have tiny heads. I noticed this first in 1985 at an exhibition of Chinese dinosaurs. There was an especially large sauropod, but its head was about as big as mine. It struck me that there is an issue of fueling capacity - how does that tiny mouth take in enough plant matter to fuel that body? When I look at modern herbivores, I observe a significant head to body ratio in the larger ones. Think elephant, hippo, cow, horse, etc. I did a little research at the time, and ran into an amazing amount of complexity around foods, efficiencies, resting versus active energy demands and so on but never did get to the bottom of it. I've never revisited that one. They existed, they must have gotten enough food, but it beats me how.
Air pressure is a funny one. It wasn't obvious to me why the pressure of a column of gas, taken at any point in the column, was equal to its weight. The problem was my "mental model" of what weight actually is. After a bit of research I couldn't find anything that addressed my concern and it wasn't until I posed my question on a forum that I got anywhere close to understanding the detail. My early introspective analysis led me to this idea: the weight of any object is a force generated by the extent to which the object is prevented from being accelerated by gravity. So I wasn't really interested in the apparent weight of an object on a scale (ie whatever weight the scale might show if other forces are applied), rather the pure notion of an object exerting a force on another object in a gravitational field due to the gravitational attraction.
Put another way, in my mental model any bounded object, say a lump of lead, has a weight in a gravitational field equal to the reduction in gravitational acceleration relative to itself. If it is at rest and not being accelerated by gravity, this would be its "resting weight". In free fall it has no weight on a scale also falling with it as it is being accelerated freely by gravity. If we could exert an upward force on the scale such that the scale falls at half the speed of gravitational acceleration, the lump will weigh half its resting weight (I think it was Einstein who observed a similar thing when he noted that a falling man was "weightless").
Now, if I am in the atmosphere, how can it have a weight, if weight in my model is the force an object exerts on another object due to gravitational acceleration? Where is my surface that can express weight on the other object? Where in the column is my atmospheric mass being accelerated by gravity and what surface prevents it from being accelerated? So my problem was how can we weigh something from within it, when weight is a force generated at the boundary between objects? At any point in the column, I am within it, so to speak. To my way of thinking, this is analogous to being inside my lump of lead. I can measure pressure, which is the same in all directions as it is a product of density, volume and temperature. But weight? Not that I could see. Of course, we can look at this another way and say that it is gravity acting on the gas molecules that leads to the variable density of the atmospheric column, and hence the variable pressure. And thus in a way, as the density is an outcome of gravity at work, weight does correspond to pressure. But not weight in the manner in which I thought of weight!! I was thinking of it as a singular quantity rather than a force...
Colour caught me by surprise. I thought colour was an intrinsic property of the world, but on inspection it became apparent that it is a quality of mental representation. Physically, in the real world, there is no light or shade, no colour, no black or white, nothing of our familiar visual experience. Rather there are simply the properties of objects in a field of electromagnetic radiation. Thus there isn't even such a thing as red, merely the property of objects to absorb and reflect certain wavelengths of radiation. And our retinal cells respond to those wavelengths and generate a mental representation that we call colour. A moment's thought tells me why this is so. Colours are used (as it seems so too is everything else our brains do in consciousness) to provide a model of differentiation. All our brains are doing is generating some way to distinguish between objects at a greater level of fidelity, and it does this by having cells that respond differently to different physical quantities. And how else could we be aware of those cellular responses?
As for the "this sentence is false" thing, well I dunno. I read a little on a philosophy site or two and am none the wiser, but I've not posed the question anywhere for fear of looking a bit dim seeing as it is apparently a paradox. I shall have to search and see if there is a thread here as Braininvat noted, it might clarify things for me. Here's what I thought on reading this one for the first time.
Language is a symbolic representation of underlying mental constructions such as ideas, thoughts, propositions and so on. So a sentence expresses something. For a sentence to be true or false, it must express a proposition. For example, the sentence "that car is red" can be evaluated for its truth condition. It is either true or false. But it's not the sentence per se that we are evaluating, it is the proposition expressed. Taken completely, the proposition is properly posed as "The sentence 'this car is red' is false".
In the case of "this sentence is false", there is no proposition. "This sentence" is a noun phrase and refers to itself. There is no proposition. We may as well say "This car is false". It is an invalid construction. We could try to nest it as I did above, but this simply leads to infinite recursion.
So I don't get it.
As you can see, things can look a particular way but once you start trying to understand the detail, all sorts of complexity appears. And part of the difficulty in understanding that complexity is your own particular approximation of what is happening. That approximation can often stand in the way of grasping something, as for example in the weight/pressure thing, or you can not realise that an everyday assumption can prove to be utterly wrong (as in the colour example). Others require a particular twist of mind that sometimes escapes me (eg the sentence paradox) or alternatively you just run out of time to explore or it gets put to one side and you never do work it out (eg the dinosaur problem).
But as Dave_O observes, it's a lot of fun trying to find out, and it's great brain exercise. Oh, and I am intrigued about what you've come up with, Dave, if you now know what time is. I've thought about that too...