A classic question regarding this is,

is the moon not there when we äre not looking at it?

I began thinking about this question when "Aaron" asked the following question

"Well, if there were no Humans, would Time Exist? Or does the existence of Time depend upon beings that can perceive it?

things tend to "exist" when someone points it out, for example, gamma waves have alot of energy, and thus, have a higher frequency.....these facts exist , because the have been perceived and "discovered".....

now, lets imagine that gamma waves hadn't been discovered and perceived in the late 1960s, would the have "existed"?

would things exist if they are not perceived, who knows, there may be MANY more particles out there that do not ëxist"because they havnt been discovered!!

For real intents and purposes, an undetectable object doesn't exist. Reality should be exactly what it's perceived to be. We can imagine or even know for certain what could or does exist beyond our ability to interact or detect such things, but in terms of science and tangible physical reality it would be unrealistic to say that unmeasurable or undetectable things physically exist.

Of course the issue here is that the physical universe does not exist identical in its perspective between people - 2 people looking at the Moon aren't seeing identical streams of photons, though the general characteristics of the Moon are shared in common.

So when two people look at the Moon, they aren't seeing it identically and hence the observation by one person of the Moon doesn't exist as a tangible reality for someone else. It's only when both extract similar features from different experiences that correlations as to quantities and magnitudes of information with different characteristics can be matched between observers, and not the instantaineous qualities each perceives this information to be conveyed by.

So a good question here would be to more accurately define to whom an unperceived object could be seen or known as existing (if it's not currently observed, yet it is known to exist, then it must be due to memories of it - are memories of physical objects representative of the existance of an object? In a sense, I'd have to agree that this could be true as all knowledge and experiences are filtered by the past and memories and even something as pervasive as gravity couldn't be known to exist without an ability to remember and correlate physical actions from moment to moment and "decode" the influence of gravity from any other "potentially random" interaction/influence/force, not determined to be representative of gravity).

Basically, an apple doesn't exist in an idealized form but instead is a nebulous definition that can range, for some classifications, from things that would hardly resemble an apple to things that might fit some idealized version of an apple for someone. The same is even true of gravity though as even gravity is not directly detected except via. its statistical influences on other directly detected forces - for example, when standing, the gravitational force itself isn't directly detected but instead the force biases orientations of atomic bonds that promote or inhibit electrical signals to propogate along them and these signals are then correlated in the brain and learned over time to represent gravity. Gravity itself is not directly detected in this case but instead embedded as statistical structures in the information that's directly and physically detected.

If I go outside tonight and scan the sky, I'm close to 50% likely to see the Moon. I could imagine it to be made of cheese or rocks or valuable crystals etc., but none of these directly influence physical experiences, though they can alter the context and subjective experience I receive looking at the Moon, but for all real intents and purposes the Moon is no more physically real than the 50% chance I have of seeing it if I went outside and looked for it, though the subjective qualities and conscious perceptions surrounding the context of that observation are also real and exist to myself, though they're just as non-directly observable as the individual photons I happen to detect as well (someone can't stand behind me and get a second glimpse of the same photons I saw, nor do they likely perceive color consciously in the same manner as I do, nor would the subjective context surrounding such an experience be the same etc. and that's why we don't all exist as the same person/being).

Ultimately reality, even from a strict scientific perspective, can't be anything other than what you experience it to be and a common objective reality is only a small subset of features that existance possesses that can be specifically counted (to be technical, it's a specific ordering of events that conveys the individual perceptions of real events, and the countable number of common features within such a demarcatable collection of events results in the objectively viewable version of the objects those events represent and effectively physics arises from counting as memory and comparing magnitudes of events over time to localize objects in common between people - for example, day and night are experienced individually by many unique qualities that aren't shared in common, though we can compare the number of day and night events between people over time and find a one to one correlation between the statistical features of these experiences representative of day and night and this allows for many entirely unique and individual experiences of day and night to exist without requiring observers be superimposed in space and time and yet still allows for the less time sensitive reordering of observations to be compared as numbers/magnitudes between people - the same goes for colors, which exist in terms of individual conscious qualities that are quite likely not identical but instead the relative magnitudes of various components of colors can be compared between people and the statistical construction of objectively agreed upon hues is created, whereas the specific ordering of individual colors of photons isn't significant or even detectable as objectively real).

Yes, I can ramble, but the point is truly that even the term "exist" is meaningless without other concepts to connect it with and the same is true that unperceived/undetect objects don't exist in any real sense because the properties that determine what that object is are only defined in terms of relationships to other objects (an electron would not remain distinctly as an electron in a universe that possessed no ability to convey electrical charge information regarding it for example, and apples are only apples because of a myriad number of features they possess that are defined by the matter they interact with and the physical form they possess which only exists relative to a space that allows for such a form to be sustained etc.)

Now just to confuse things a little more I'd have to actually say that likely any and everything does exist, though not instantaineously and what aspects of that "everything" a specific observer happens to recognize are determined by properties unique to their figurative vantage point and filtered by their own form and ability to interact and correlate information they detect - it would only be between "beings" sharing common communicable features (and specifically at least 3 distinct such features, though realistically internally possessing more) that any version of a shared of objective reality between them can begin to be constructed (and that's why space appears to exist primarily, in it's lowest common form as a 3 dimensional space as you need at least 2 traits to represent binary information and a minimum of one more to demarcate time between symbols, unless you're working with quantum information in which the time synchronization isn't present and you're left with instantenous transitions between probailities of states, but these don't have an ability to communicate an objective version of time and a particular sample is determined by the observer and not externally communicable - yes, I know this stuff is overly technical but I've got to toss out some breadcrumbs that a few people might be able to follow later).

So there's truly an issue over what form of existance is being referred to, though in either an objective or subjective reality, if someone can't perceive something, then truly whether or not someone else does is rather irrelevant in that the reality becomes one of seeing/hearing/knowing someone else is making a claim that something is real, and not that someone claiming something is real actually creates reality for you (science would be in trouble if we were expected to use that definition of reality).

Also, to repeat some of the above, for science, reality is a product of what influences can be predicted by the assumed existance of something. If predictions do not pan out to be anything other than prior "random" assumptions, then that "knowledge" is useless in terms of science. So by this definition as well, if an object can't be perceived, then there is nothing to predict regarding it and it doesn't exist as provable real, in terms of a scientific view.

The real issue at heart here is that people tend to prefer others sharing a common objective reality and though someone else may not experience or otherwise detect the presence of something, there are often social pressures toward someone adopting a similar (if imagined) view of reality and this pressure shapes much of the institutional views in science as well as agreement on what reality should be defined as can be preferential to actually physically measuring and understanding it (history is filled with examples of such socialized versions of scientific knowledge). Of course, having common terminology is great, but ultimately not an absolute requirement, IMO (as I truly think someone sitting on a rock thousands of years ago could potentially figure out much of modern science and technology ... then again realistically might not be able to easily take immediate advantage of such knowledge as the tools to operate on different physical scales and realms of properties wouldn't necessarily be available).

Yep, now I'm really rambling. I better stop there but hopefully you can extract a few nuggets of information from the above comments.

Unfortunately the poll does not allow for one to answer both yes and no. "Existence," is a relative construct IMHO, as with the junk to the one that is the treasure to the second.

Best,
Raphie

Imagine a machine which is a box with a door. Place an object in the box, shut the door, and the machine shields all interactions between the object and the universe. When I open the box, what will I see? Will it be the same thing I would see if I had placed nothing in the box before closing the door?

For something to exist it must continually interact with everything else in the universe. This is Mach's principle.

On a side note, the interactions may very well be those interactions that mediate gravity, frame dragging, centripetal force, etc. (i.e. space-time) and may also be those hidden variables that add apparent randomness (more accurately, pseudo-randomness--if there are finite particles in the universe) most apparent in very low-energy interactions.

I voted Yes. The colors Ultra violet or Infra Red exist even when they are not perceived by humans. So to say that only those things that science currently has the knowledge of as "exists" is naive.

To the question "is the moon not there when we are not looking at it?", cannot be answered honestly by anyone. We can only say "I don't know".

Yes and no. According to the Copenhagen Interpretation of quantum mechanics, when an object is not being measured, a field of probability (The wavefunction), strongest where the object is most probably to be, spreads out over time. The longer it is left unobserved, the larger it will grow, and the more evenly spread out it will be. When it is observed, the wavefunction collapses, and the object is definate. So, to answer your question, the object is sort of there, but not in a solid sense.

- Gehn

We did not observe dinosaurs. No-one ever has seen a living dinosaur. Does that mean they did not exist? Obviously not.
Just because we are not observing something does not mean it doesn't exist, or is irrelevant, even to a scientists.
Why? Because what we're not observing can still interact with other objects which we are not observing, which in turn interacts with other objects we are not observing, which in turn interacts with an object we ARE observing, yielding evidence that the original object existed all along. If observation were some magic field of view that allows incorporeal objects to materialize, then indirect evidence would be non-existent.

The question as posed is meaningless and invites answers which will depend on multiple interpretations, ….which we already see posted.

The question can be asked properly in one of two ways,… both of which depend completely on the definition of ‘reality’ being inquired, and therefore will answer themselves. We can see then that this question is a analytic proposition which is true or false by virtue of its definition only.

1) Does noumenal reality exist?,….. that is, does reality in and of itself, independent of perception, exist? Obviously, by definition, such a question cannot be answered except by way of faith. If it cannot be perceived it cannot be known.

2) Does phenomenal reality exist when its not being perceived? Here again the question answers itself by way of definition. Since the definition of phenomenal reality necessarily involves subjective observation, the answer must be no. A Phenomenal event requires an observation to have meaning.

Thats a purely logical answer,..now for the practical,...

The primary methodology of science is induction, which draws general conclusions (synthetic propositions) from particular observations, and presumes causality as a operating premise. This reasoning is based on a constant conjunction of particular events which in principal could be effected by undiscovered laws,.. therefore science can never attain to absolute certainty,.. only various degrees of probability. Does the moon exist when we don’t look at it? Probably, we believe it to.

Analytic propositions are self contained and can attain to certainty but we can’t learn anything new about the world, …while with synthetic propositions (scientific induction), we can never attain to certainty, but we can learn new things about the world.