Nothing is certain

Existence exists. But does it, really?

Let us consider, firstly, the language-game problem. When we use the language 'existence', to what do we refer to? Something that has been described as "the most abstract notion that humans have" by medieval philosopher Duns Scotus. Our language, we take for granted, has a very simple connection to reality. I.E., the naming of a word will formulate a direct correlation and symbolic representation of the ontic thing-in-itself. This is far from true, but most especially for abstract concepts. What does the word "existence" mean? The dictionary defines it as something having 'actual being'. Clearly, it is a term that the authors expect the reader to be able to logically already understand, or, as it were, simply deduce from such a definition. Thus we understand when, asking a 12 year-old to name a list alphabetically, and he slips one up and continues, but in response to us he replies "But I thought that one was?".

Judging by the dictionary's definition, it appears that they are trying to say that 'existence' is being in reality, as actually existing. Existence is not more than a series of phenomenological events which humans have experienced throughout their lives, their history, and thus termed. The identity may be akin, then, to something like A=A. Yet this exists only in a symbolic dimension, having a very questionable relation to reality (the ontic) itself. Allow me to continue this train of thought, our so-called "science" has had immense struggles with this question of language, which is quite surprising to hear of, really. How much human perception penetrates into the so-called "sacred facts" of science is this: in previous times, the concept of sexuality has been explained by the same "scientific method" in completely different ways over history to adapt to the societal order of its time and subjugate women. Indeed, there were changing definitions for the apparently integral concept of gender itself. Let us note that gender, which has been subject to such messy splicing, is decidedly less abstract and obscure than 'existence', being an immediately recognizable binary in real life as per evolutionary measures.

Now you see the immense contentions with even understanding what existence is, as a concept. It surely is an attempt to make a bridge between the symbolic and the real. Yet this bridge is one between two great valleys seperated by a great chasm, from which fog obscures all. I understand existence to be the standard series of phenomenological actions that humans have unto life's end. You perhaps were thinking on Descartes when you set forth your statement.

Although we have absolutely no means of articulating it, let us assume that existence is what I previously just referred to: a series of phenomenologically linked events until the end of life. I must warn you that if you dispute this definition, you are running out of a ditch and into bear-traps because concepts such as the "self" and "consciousness" have been seriously challenged in the 20th century and beyond.

If one were to attempt to prove existence to be a 100% confirmed fact, you must admit that you cannot say that other people certainly exist, only yourself. But let us take this a step further; what defines existence? The brain experiencing things, supposedly. And what constitutes an experience is itself also an intense subject of scrutiny, for it is all we know just as existence is all we know. We do not know the antithesis of either of these, but only assume a void of them which we cannot anyhow imagine. Thus the fallacy of A=A.
But before I go on any further in this tangled web, I await your reply to clear up your position on the properties of existence and the information I have introduced.

My response was an attempt to introduce the intricacies of language and to point out the extremely fragile link that words themselves (specifically of abstract concepts such as 'existence) have to actuality.

As to my confusion over the various definitions, I was unsure of your own meaning. Thus, I was running through the various possiblities and chose the strongest concievable definition you might have. However, your definition, you now say, is "having objective reality or being", which is considerably different from what I defined. This makes matters somewhat simpler.

Here I will try to show that the definition that the opponent is using cannot be certainly verified. When we say certain knowledge, we mean that this thing is entirely undoubtable; not a shred of doubt can be formed.

What does existence entail, then? According to the opponent, it is having objective reality or being. In that case, let us assume that tomorrow the opponent woke up to find that his entire life had been a dream. He wakes up on another planet, with differently concieved forms of sciences, matters, etc. This entire dimension is vastly different and he is concieved as a different form of energy and matter. Does that mean that he, the person he currently is, ever 'existed' according to that definition? Surely, a dream cannot be 'objective reality', but whatever it is, it is where he had existence. But let us go even farther and assume that the dreamer had absolutely no connection to the opponent, but instead was just dreaming of this individual's life randomly, as it may happen, and with absolutely 0 link to the other world other than that they were the ones dreaming of it. Thus the property of identity is cancelled out. Let me stress that I am contradicting existence by your definition specifically.

Taking this line of argument further, let us also postulate that the entire world was the dream of some god (as some religions do advocate). Therefore, no objective reality would exist, and you would not exist, and you would be as far from the dreamer as a gnat would be to you.