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[modest]

Originally Posted by arkain101

The question is, in scientific terms, what exists and how do we know that it does exist?

[...]

1)What our senses can tell us exists
2)What reasoning, mathematics, and experimental data can tell us

Immanuel Kant said (and I agree):

Originally Posted by Kant

All our knowledge begins with the senses

Without them we would have no link to the natural world and knowledge of it would be impossible. Of course, this does not mean we need to observe each and every thing that we reason exists. The rest of Kant’s quote:

Originally Posted by Kant

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

This indicates to me that a person’s ability to reason allows them to deduce the existence of something they may have never personally experienced.

Originally Posted by arkain101

Starting with #1, one way we can prove things exist is through our sensory capabilities. If we can see it (sight), touch it (spacial awareness), smell it (scent), feel it (texture touch), hear it (sound), taste it, then we can know that it exists. Why? I think if it can affect us, then it exists.

Some forms of empiricism go as far as to claim that we can have no knowledge of the existence of objects outside ourselves—that we can’t know these objects in and of themselves. All our knowledge and understanding is of sensory perception, and that perception is all that we can prove. They say we can’t truly know an object, we can only know our perception of such an object.

For example, if we see and feel a raindrop then it is not the properties of the raindrop we are proving, but only the properties of our sight and touch which create a mental representation separate from whatever a raindrop really may or may not be. This is known as Phenomenalism or Subjective Idealism of which George Berkeley was a famous proponent.

I do not personally subscribe to this philosophy.

Originally Posted by arkain101

The other is when we exclude all our sensory methods. How then can we test and define that something exists?

One could say, we know something exists if it has the ability to affect other things that exist. Say what?

If I try to describe the universe when excluding the awareness produced by senses, that is, to exclude the consciousness, I end up with trying to explain that which is not absolute.

To completely “exclude all our sensory methods” or “exclude the awareness produced by senses” would make any determination about material existence impossible. Some things are not *directly* observable by the 5 human senses. A good example is radio waves. They are, as you say, found to exist by their effects—but, this doesn’t mean our senses are being excluded in the process. As with the case of radio waves, we are using our ears to listen to the radio to determine the waves exist.

Originally Posted by arkain101

For example, Let's say I know an object exists because it can have an effect on another object. This lets us know it exists but it does not define how. Or, I know light exists because it has an effect on an atom. But why do I know that atom exists? Because it produces energy?

Do we have nothing absolute to fall back on as to be positive? Even if we had a fundamental particle, in what way can we prove that it exists without falling into the trap of producing more questions?

The problem is, when something = something it is, duplicating the obvious. 1 = 1, which is to say 1 = 1, did I flip the numbers around? it is impossible to tell, and the whole of the equation simply means 1.

It is a conundrum, I agree. Nothing can be seen or said to exist in isolation and nothing can be seen or said to exist apart from observation. Philosophers might say that the one “absolute to fall back on” that you’re looking for is expressed by René Descartes in 1637: “Cogito, ergo sum” (I think, therefore I am)”.

Originally Posted by Descartes

But I have convinced myself that there is absolutely nothing in the world, no sky, no earth, no minds, no bodies. Does it now follow that I too do not exist? No. If I convinced myself of something [or thought anything at all] then I certainly existed. But there is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me. In that case I too undoubtedly exist, if he is deceiving me; and let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think that I am something. So, after considering everything very thoroughly, I must finally conclude that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.

-Descartes,

To put this in modern parlance, think of being in the Matrix (a computer simulation where everything that looks real is actually a simulated deception), nothing that such a person observes can be proved to actually exist in the common understanding of the word 'exist'. The only absolute that such a person can prove is their own existence. If the person can question their own existence, or the existence of anything else, then they must exist.

Originally Posted by arkain101

This takes me to a final query, When studying the physics of the universe, what are we studying? Things seperate of our senses or things produced by our senses?

Is there a field of study that truly excludes our senses? I believe this could be quantum mechanics (quantum material), and that may be why we can not understand it, that is, it behaves in ways that our senses disagree with.

It is possible (and even very probable) that physics describes the universe as it would be without human observation. But, I can’t think how this could be proved. Ultimately, testing the laws of physics is done with human observations—so, it’s impossible to take ourselves completely out of the equation.

I believe this would be true with quantum mechanics as well. The state of a quantum mechanical system which can be measured is called an observable. It is only through measuring and observing that we can infer the existence of anything quantum mechanical.

~modest