This proposition is not a contradiction, although it seems somewhat illogical.
The simplified version should be “Can’t find it, do you still have it?”
If this thing belongs to matter, but is completely isolated, and is not felt by the subjective consciousness of living things in any way or in any form, can it be confirmed that this thing exists or does not exist?
This is a very interesting philosophical question. I will not state the various ideas in the history of philosophy (in fact, I can’t remember it), but just talk about an idea that I think is more interesting. When we say existence, we often understand it as an abstraction of concrete beings: the table exists, the chair exists, you exist, and I exist. But being is not a concrete being. This is clear and straightforward, and it is easy for everyone to understand. Then, existence is different from being. If the two concepts are an abstract relationship, then what kind of abstract relationship is this? For example, in the world, there are people who are close to a circle, and there is an abstract concept of a circle. What is the relationship between the two? In my opinion, there is no other relationship between the two, but a connection of imagination. Abstract existence is nothing but a predicate that helps to outline a concrete being, a name, not something that exists in the world independent of beings. Therefore, the world is not separated from the existence of beings. The use of being separated from being is a misuse. So, if a thing exists, then there is such a thing. You say that a thing exists, but it does not produce a connection between time and space and causality. How can you prove that it exists? Of course, in philosophical discussions, we can imagine an existence without a causal connection between time and space. If it is possible for the existence without the connection of time and space, then this existence is possible. If this is inevitable, and it must be derived from conceptual analysis, then it must exist, although this is impossible in my opinion. If this is impossible, then such an existence is impossible. According to the title, suppose that if the being without the causal connection of time and space is real, then such a being is real. However, the premise is probably wrong.