How is physical reality affected by the act of observation?

Question

I actually read that in a Buddhist book, saying that the act of observation affects all matter. Later it says matter more of an event rather than a reality.

Answer 1

At a macroscopic level, it is not, at least not at a level that can be quantified.

At a quantum level, observation of a particle changes its position and velocity due to the interaction of the photons used to measure it.

Answer 2

Here's an example of how physical reality could be affected by "an act of observation". If I have a polarized beam of light of unknown polarization orientation, I can measure the intensity of the beam passing through a polarizing filter, so that if the intensity passes through 100%, the orientation is aligned with the filter, and if it intensity drops to 0%, the orientation is aligned perpendicularly with the filter. But the act of making such an "observation" impacts the properties of the polarized beam. If I have a series of 2 "observations" using polarized filters oriented perpendicularly, the beam intensity will drop to 0%. However, if I did an "interim observation", or using a polarized filter set at 45° and placed between the first 2, then the final beam intensity drops to 25%, not 0%. Thus, what happens to the beam depends on the observations you make on it. Intuitively, we have the idea that an act of observation can be done "unseen and unfelt", as a spy would observing actions inside a compound, but in the microscopic world of quantum physics, that's not possible. Any observation one makes impacts the object being observed.

Answer 3

This is really an open question, with no satisfactory answers.

There are literally dozens of ontological interpretations of quantum mechanics, each with its own particular flaws - see Roger Penrose' "The Road to Reality" for a good account.

Bascally, at the macroscopic level they have no effect. Which leads to a problem with the Copenhagen interpretation that most people on here have heard of and spout. This says that a macroscopic observation of a quantum system collapses the wave function. However, it does not say how a system knows it is macroscopic, what constitutes such an observation and where the line gets drawn. This is a huge problem, and means statements like "the act of observation forces the quantum system to choose or fall into a particular state" just make no real sense at all.

Answer 4

Well, I'm guessing you're talking about quantum theory here. So I'll answer it with that in mind.

According to quantum theory, particles can have multiple states at once, call quantum superposition. As soon as an 'observation' is made on that particle, though, the superposition state collapses into a single state. So, in essence, when you observe it, you 'set' it. Think of it as jell-o. When it's just made, it's all runny (just as when the particle is just released, for example, it has multiple states) and then when you put the jell-o in the fridge, it sets, and takes the form the container (just as the particle 'settles' on a state when an observation is made)

Answer 5

According to some doctrines of quantum theory, there is no reality apart from observation. See the "Schrödinger's Cat" thought experiment to get more insight on this.

Answer 6

Observation causes reality to chose a particular outcome. Without observation, reality is a superposition of all possible outcomes.

Answer 7

This is related to the Heisenberg Uncertainty principle.

Here is some articles that explain it:
http://www.physlink.com/education/AskExperts/ae179.cfm
http://home.comcast.net/~neardeath/science/001_pages/37.htm

Here are some articles about Schrodinger's Cat:
http://www.phobe.com/s_cat/s_cat.html
http://en.wikipedia.org/wiki/Schr%C3%B6dinger's_cat