Will I be ridiculed if I use the word in such a way as “the odds of your finding a job at your age are metaphysical impossibility,” in the conversation with my friends?
I think you'd want to avoid using the word metaphysical – unless you are dealing with the metaphysical realm.
I just looked up metaphysics in NOAD, and I can see why its meaning might not be crystal-ball clear:
metaphysics (pl. n.) the branch of philosophy that deals with the first principles of things, including abstract concepts such as being, knowing, substance, cause, identity, time, and space.
Some examples might help. By and large, I think these would fall into the realm of the metaphysical:
- witchcraft, voodoo, and spells
- time travel
- using crystals to channel healing energy
- the ability to see into the future
- the ability to communicate with the dead
As Bill Franke said, in the Time article, the usage of the word works, because the author is talking about being able to deliver a eulogy at our own funeral – a metaphysical impossibility.
Why is it specifically “metaphysical”?
M.I. (metaphysical impossibility1) in this context refers to the inability to talk at our own funeral – not give an Academy Award speech. The reference is a subtle dig at Academy Award speeches in particular, which are known for being repetitious: once you've heard one, you've heard them all. These oft-parodied speeches are usually a litany of thanks toward people we don't know and we'll never meet. Because all two dozen or so awards are presented on a single night – by actors, to actors – these sometimes emotional acceptance speeches can get rather monotonous, especially since the awards of most interest to viewers are given toward the latter end of the ceremonies. Because of this, the writer compares the viewing experience to that of a funeral – another place where you see person after person get up and say something. However, the writer is also acknowledging that this analogy is somewhat fragile, because, at an Academy Awards speech, the actor is speaking about their own accomplishments, whereas at a funeral, people are speaking about the person in the casket. So the only way the analogy would really hold is if you could watch someone speak at their own funeral – a metaphysical impossibility.
1Lest anyone be misled by my tongue-in-cheek initialization, M.I. is not a standard abbreviation for metaphysical impossibility. As far as I know, metaphysical impossibility is not a commonly-heard expression, either.