I am having some troubles with the whole notion of materialism which states that only matter exists. Doesn't stating that something exists presuppose the idea of existence/being, and therefore that this idea itself also exists? So if "only matter exists", i.e. all objects are material, how can being be an objective attribute of objects without existing? For that matter, how can any attributes that distinguish objects be objective without existing? It is not like attributes can be material.
"I am having some troubles with the whole notion of materialism which states that only matter exists,namely how can be said that only matter exists without implying the idea of "existence /being " ?"
It is confusing because most people who say that don't know what it means in the technical philosophic sense. They usually just mean that they are into science. In the strict sense it is a claim about the nature of a secret inner core of a thing, the substance, which is not the thing we see, the mere appearance. When Penrose says math really exists, he makes a claim about the nature of homogeneous Philosophic Material.
Dennett speaks of “one stuff”, i.e., one hidden substance which consciousness represents through the appearance. In his sense it amounts to the same thing as saying consciousness is a an illusion, or, almost an illusion. Reducible to the one stuff.
In the Heideggerian sense it means there is something that is there, e.g., a chair, and we understand it as something, a chair. The claim is that a thing and the way it is understood both lay in a shared being. Da(there)-sein(meaning). The “-” dash is being.
Kant says, contravening Heidegger, when I have something which is something, I add no more by saying, it is. Is is the “cupola” of a sentence. People like Russell exclude the sentence, and hold that it has no proper existence.
First, most folks (with various exceptions e.g. Meinong, David Lewis) buy Kant's argument: Being does not add meaning, because it is not a property, or at least it is just a reflection, and not an objective property that conveys meaning. You can't implying 'something more exists' by not saying anything.
To see this in more detail: If a property actually conveys meaning, its applicability can be tested against some criterion. Also, properties have opposites. So if existence were an objective property, nonexistence would also be a property. As the opposite of existence, it would also be objective, and so could be tested. Well, to what would one apply the test for nonexistence? I cannot put a nonexistent unicorn in any hypothetical machine and press a button to judge whether it is really there. By contradiction, we have a proof -- existence is not an objective property.
If you allow the test to be applied to a reference to the object, then existence ends up being one modality among many, depending upon the kind of reference: unicorns exist, but only fictionally, they can be referred to in stories; guilt exists, but only morally, it can be assigned by a set of principles; many future versions of me exist, but only potentially, as things that refer to me as their past... We need another sort of logic for modalities, and what we have is very incomplete.
Second, no materialist has ever denied there are things other than matter. Matter itself cannot account for motion, so there is energy other than matter (even if matter is energy, energy is not matter.) And beyond that even matter in motion cannot account for generalizations made about those motions, and the statistical trends there are obviously exist in some sense. No materialist denies this, either. So your statement 'only matter exists', taken completely literally, is already silly, even to the most dedicated materialist. It is a straw man.
But the notion of modality gives us a less elusive way of stating the proposition of materialism: for a materialist, the modality 'physical' is more basic than the modality 'actual' -- so that anything that exists 'actually' also exists 'physically' -- I can point at it or locate it by coordinates, referring to it in a physical way, or I can identify it via its effects upon other things that I can refer to physically, in a way consistent with physical observation.
(This is a reasonable and meaningful statement because we have examples of other modes related in this way. Possibility is more basic than actuality or morality: anything that actually exists has to potentially exist; anything I really ought to do has to be possible.)
This might be true. But we can't tell, because since quantum dynamics, the notion of locality, and therefore the modality of 'physical' seems to be impossible to define: Is there a boundary on 'physical'?
Here's an eastern perspective drawing upon the legacy of Islamic philosophy, and in particular the most distinguished school among them known as Transcendent Philosophy (or rather Theosophy) founded by the 17th century Persian theosophist, Mulla Sadra who lived through the period of the Islamic-Iranian Renaissance. So a rather extensive introduction comes first before the actual answer.
The cornerstone of Mulla Sadra's philosophy is the theory of "primacy" or rather "originality" (Arabic: "isala") of existence or being compared to quiddity. For Mulla Sadra, existence is considered to be the principle of all things that are perceived and captured by their quiddity or "whatness". Hence things don't exist by the virtue of their whatness, quiddity or essence rather through their existence. So existence is the principle of everything, while things or quiddities are only manifestations of existence.
For this thesis to be true, existence has to have a simple, undefinable, indefinite, irreducible reality that happens to be the source of all that is composite, defined, particular, and concrete, features that are captured in their quiddity. Why this is true is very evident: Nothing can be the thing it is if it does not first exist! So quddities be it substances, accidents or qualities etc are always secondary to the existence of things.
On the epistemological level, existence is believed to be self-evident as a concept. Self-evident concepts are so precisely because they are ontologically the most basic and consequently the most fundamental realities. Hence a coherent link and harmony is realized between the epistemology and ontology when existence is considered the most original and fundamental reality.
From this follows that a most fundamental reality would also be the most intimate reality to our consciousness since if it is really fundamental it has to constitute and therefore accompany everything including our consciousness as a quiddity. So the intuitive clarity of existence is itself a testimony of its fundamental reality as opposed to quiddities as secondary realities that have to be acquired by experience and learning and/then be cast into definitions to become comprehensible and communicable.
This contemplation reveals precisely why existence is no more "objective" — in the sense of becoming "object" of anything — than "subjective" because existence as the principle and determination of everything can never be a determination of either the external world or human mind. So the reality of existence is neither subjective nor objective, although as a concept it is applicable to everything but not in the conventional sense of a predicate that adds anything to the subject, since predication of existence is in reality always an inverse predication where the purported subject is in fact predicated upon existence not visa versa! So propositions in terms of "A exists" in fact express the original proposition, "Existence is here and now manifested in A" or rather "this existence is A".
This much elaboration I think is sufficient for the purposes of this question as this is not supposed to be an introduction to Mulla Sadra's doctrine of originality of existence and its far reaching implications, a philosophy that brought a whole revolution to both Peripatetic and Neoplatonic philosophical traditions of his time and with an inherent potential to influence world philosophy.
Based on the above thesis, the answer to this very reasonable question becomes now evident: "Matter exists" can only mean "existence is manifested here with the attribute of matter." So it is not that matter exists but that it is rather determined by existence. This much establishes that existence or being is rightly not material but also not even immaterial but a reality above both material and immaterial that determines both! Call it God and Mulla Sadra would agree! ;)