Philosophy Of The Cosmos - Observation Vs Measurment
Do I measure something when I look at it, or sense it in any other way?
I suppose what I am trying to find is a solid definition for what a measurment is. I think that this might be important for some of the interpretations of quantum mechanics.
So, it to mearely be aware of an object enough to say that you are measuring it? Basically what constitutes a measurment? Interaction with the object in question?
Is a dog making a measurment of the grass it stands on? What about a sea smail measuruing the ocean floor?
Here's one: Are plants measuring their surroundings, as they certainly interact with them (take water from the soil etc)
Another thought: A while ago in lectures, Jason was talking about underlying reality and brought in an example about a schizophrenic's reality. Although it was pointed out that this was not what we meant by underlying reality, if the schizophrenic sees/hears (ie measures ??) something that others cannot, is that something, for quantum mechanics intents and purposes, real?
Actually, I think that I may be getting this last bit wrong. I think that the Copenhagen interpretation does meas that
no measurment => not real
but the converse it not true
ie measurment =/> real
Right, glad i sorted that out.
Kathryn Parker u 4845956
Hey there,
This are some of my thoughts, please feel free to criticize them.
I would think that a measurement is when we observe something and can explain or understand its characteristics, because for this we need to understand for instance its length, size, weight, heat and so forth. However, this is more a personal interpretation or description than anything else.
Whether an animal or a living plant is making a measurement often depends on its cognitive or nerve systems functions. Because, in order for something to measure something, surely it must be capable of observing or experiencing something (temperature, texture, size, softness etc.) in the first place. Thus, plant most likely cannot measure something consciously, but they do register a change in temperature and react to it. Is that then already a measurement? Therefore, it does more depend on what one understands under measurement, than on the animal or live form itself and the tasks it is performing.
To your schizophrenic point.
I do not think that it is the same kind of measurement or observation. The reason is, that what he see's does not originate from a physical world, but rather is just an electric impulse in his brain. Whereas something that is from the physical world that we can observe, for instance seeing things through means of light particles or waves being captured through the eyes. Therefore, I would think that in quantum mechanics, this would not be considered 'real'.
However, the counter argument might then be. Well, it is as real for the schizophrenic looking at his imaginary projection, as it is for someone who is no schizophrenic looking at the 'real' world. However, the only way to differentiate between them is through proof or evidence. Either through someone else's observations or other reliable means (what ever they might be).
The copenhagen interpretation? Well as I understood it, something that cannot be measured does not exist (within its interpretation or system). On the other hand when one can observe and measure it, it exists within its framework. The question however is, what do we mean with 'real'. However, this is also not too clear to me. Hope someone has a better explanation then I have.
Hope this could be of any help what so ever.
None of this is clear to me either. It's a real sticking point for the Copenhagen interpretation.
I'm pretty sure that according to the "observer" (Wigner) version of the Copenhagen interpretation, anything conscious measures everything it senses, and this includes most if not all multicellular animals, and all senses, not just sight. Beyond that, I really have no idea. Maybe this is because the Copenhagen interpretation is too vague; maybe it's because it's false; maybe it's because I'm being dumb. I just don't know.
As we'll see in about an hour from now, some other versions of quantum mechanics don't have this problem.

I've been thinking about this too, and am quite confused by the same problem. An article I read the other day (which i talk more about in discussion topic here: ) suggests that this problem occurs because this sort of physics actually suggests a collapse of the distinction between the observer and what is being observed (or the person who measures etc etc).
But that still doesn't get to the difference between observing and measuring. The questions raised here seem to be centered around the links between observation or measurement and consciousness and also rationality - philosophical questions which are notoriously difficult to deal with. What makes an observation, observer, measurement a rational one? Is the schizophrenic actually that irrational? Does it have to be made by a conscious observer or a self-conscious one? What is the difference between those anyway? Is there really such a clear dichotomy between subject and and object or observer and phenomenon?
I'm sorry this post probably isn't that helpful!!
And, as Jason says, possibly the Copenhagen Interpretation is just plain wrong, or way to vague, anyway!