The Self
Assuming that statement is true, why not.
Again sans religion... yet you mention the metaphysical. Interesting. We'll call it spiritual I suppose.
Which does mean mankind though perhaps animals as well have or can have qualities that transcend this existence. Of course for the sake of theory you could say objects do too.. again for the sake of theory.
Which begs a whole multitude of other questions ie. is a few million grains of sand any different metaphysically than a sand castle formed of them? Etc.
For the sake of argument I'm going to assume we mean "the self" which again varies.. the essence, the soul, our memories, persona, something deeper even or comprised of one or more of the aforementioned is "a thing" in a form that transcends biology. Or is that what it is defined by? Hardly metaphysical if you ask me. If it is solely biologic the self is the conciousness, formed by the body and its senses. Memories, experiences, etc. to constitute an identity. If not.. that's when the argument gets interesting.