If a proposition is true when it describes something that does exist, then a proposition is false when it is a description of something that does not exist. And so many times we ask whether it is true when someone makes a statement about things they claim to exist. And related to existence and non-existence is construction and destruction. For the process of coming into existence is construction, and the process of going into non-existence is destruction. Nothing exists without going through the process of construction.
Nothing ceases to exist without going through the process of destruction.
For just as true is the negation of false, being constructed is the opposite of being destroyed. A thing cannot be both built and destroyed at the same time. Nor can a thing be neither in the process of being built and destroyed at the same time. Either the parts are coming together, or they are falling apart. And as any set of circumstances is in the process of coming together, any alternative of those circumstances is being destroyed.