If you like thinking about the nature of reality or consciousness or cool things in general, and are unfamiliar with the double slit experiment, you must watch the video below (or any number on YouTube). In 10 minutes you may be completely flummoxed by a foray into the quantum world.
I am no physicist, and I’m certainly not qualified to be sharing my opinions on such things, so I can’t think of a better topic to discuss. The experiment clearly shows the act of observation has some affect on the way we perceive light to behave. I emphasize perceive because that is a much different statement than claiming the act of observation changes the behavior of the particle. I do not think our observation changes the behavior of the particle, I think it changes what we perceive. Not that we are necessarily looking at two different things, but that we are viewing another side of the same coin. Through observation we collapse the dual nature of light (particle and wave) into one particular incarnation, a particular particle. Through observation we define a path.
The act of observation occurs at a specific instance in time, and at a specific instance, the entity has to be exactly somewhere. This only occurs at the smallest possible increment of time (theoretically possible), exemplified by the derivative. As the light is traveling through space, you cannot distinctly define its position unless you freeze time. The act of observation is this act of momentarily freezing time. The Heisenberg Uncertainty Principle is the relationship between two complementary variables, for example, spatial position and momentum. There is no way to simultaneously know both the position and momentum of an object. If the object has momentum, it is by definition moving. If it is moving, it is by definition not in a fixed position. This can also be completely defined through the lens of time. In order to know the exact position of a moving object, time must be stopped. However, if you stop time, then you stop velocity, and without velocity you have no momentum. So the idea of complementary variables is the idea that the closer you are to pinning down the value of one variable, the less you know about the other.
It is as if through the act of observation we are assigning destiny. The act of observation freezes time, and in that moment, everything must be spatially accounted for. All possibilities collapse into a particular output, all momentum goes to zero, and a precise position is required. Then instead of perceiving the possible outcomes of traveling light (wave behavior), we perceive the outcome of that distinct particle which was observed.
It might make sense from an abstract “energy” point of view. It would be energetically more efficient to simply define a cloud of probability (wave behavior), than to output a specific path (particle behavior). Without an observer to output to, why waste computing power or energy to display an output?
There is some connection to consciousness expressed in this experiment. I do not think the observation itself has to be “conscious,” but the experiment is somewhat analogous to the idea that things only exist once they enter our field of consciousness. At this moment, look straight up. The ceiling or sky you just visually perceived (or mentally perceived if you actually didn’t look up, and are now just thinking about that ceiling above your head) was nowhere to be found in your conscious experience until the moment you perceived it. It had no defined real estate in your consciousness before, but there was certainly the possibility of it appearing in your consciousness. As soon as you bring your awareness to the ceiling, it exists. Your awareness is just like the act of observation in the experiment, calling forth a specific entity from the nebula of possibility. Consciousness has to filter down the possibilities of reality and present us only with what is of the highest importance. It is energetically impractical do discretely define all of reality, we must operate with a nebulous or probabilistic understanding of most things at most times. Light only behaves as a particle when it is forced to, when the act of observation demands certainty. We trade variety, novelty, and open possibility for limited but discrete understanding.
Like I said, don’t trust me on this. This is no more than a neophyte thinking out loud. However, I do hope it makes you think for yourself.