Anthony Hopkins gives the performance of a lifetime in “The Father,” which is saying something for a man who has been acting professionally for more than a half-century, and who already has one Oscar to his credit.  Hopkins is 83, at the top of his game, and also of the right age to infuse his character in the new film with the most assuredly correct amount of pathos and humanity, and elicit our sympathies.  It’s an absolute masterpiece of a performance, in a career not wanting for exceptionalism.

As “The Father” commences, Hopkins’s character, also named Anthony (though with the English way of pronouncing a hard “T” sound) is visited by his daughter Anne (Olivia Colman, flawless as ever).  She announces she is moving to France to be with a new man friend and thus won’t be able to visit her dad as often.

“What about me?” Anthony pleads, with one of the saddest puppy-dog faces in many a cinematic eon.

It is clear that Anthony is in the early stages of dementia, and Anne is frustrated that her father has chased away several carers she is paying for.  But off to Paris, she says—she must go.  Anthony watches her leave from the window of his London flat, with Hopkins imbuing this wistful gaze with the same quiet ruefulness he brought to the silent suffering of his stolid butler in “The Remains of the Day” nearly 30 years ago.

Soon, while making lunch, and enjoying a recording of a rather lively opera, Anthony feels something is off.  He creeps into his living room to find a gentleman there (Mark Gatiss) casually reading the morning paper.  Who is he?, the pensioner demands to know.  The fellow claims to be Anne’s husband, but Anthony cannot recall him—and shyly chirps out that Anne has gone to Paris to be with her lover.  Impossible, the visitor says, as he and Anne live together, not far away from this very flat.

Something is amiss, and Anthony’s reality and our understanding, or lack thereof, of it will only unravel further.  Is his mind playing tricks on him?  Is he dreaming?  Things are certainly not helped when Anne returns to check on him, but is now played by the actress Olivia Williams.  A short time later, Colman returns as Anne as if she never left, but now with a husband named Paul (Rufus Sewell).  Paris?, she says, that’s ridiculous, Dad.  Confusing, to be certain.

“The Father” cleverly, and sadly, experiments with the notion of consciousness as few other films ever have.  Ingeniously, writer-director Florian Zeller, who adapted his own play along with fellow dramaturgical heavyweight Christopher Hampton, allows us no objective point of view.  We are forced to experience Anthony’s small world through his own eyes, even as his frames of reference seem to slip away in real time.  We are as unsure of what is “true” as he is, making the film incredibly effective.  Few other directors have ever so successfully toyed with the notion of what is reality—David Lynch chief among them, but Lynch fashions his stories such that it seems we are watching a dream, whereas Anthony’s waking life, if indeed that’s what it is, is a living nightmare.

And because Zeller never allows us time to reorient or regroup, we have no choice but to walk this journey of mental decay with Anthony.  There will be no great reveals, no secondary character informing where and when we are.  This is extraordinarily frightening stuff, as when you can no longer trust your own eyes, who or what can you trust?  The film has a harsh answer: absolutely nothing and no one at all.

I watched three of my grandparents decline into various forms of dementia, and it’s a curse to behold the shell of a person you knew and recall as once being sovibrant and funny.  Your memories are no longer shared; you may as well be a stranger to them.  Many a film has dealt with encroaching dementia, but from the caretaker’s side.  Here we are trapped with Anthony inside his own entropy, the only conceivable escape from which can be his final demise.

Hopkins has never been better, and when the eventual, inevitable highlights reel of his acting life is rolled after he is no longer with us, doubtless it will include the horrifying, heartbreaking, excruciating moment when he asks, in all seriousness, a most awful question: “Who am I?”

But save your tears, as Anthony will shortly thereafter cry out for his long-deceased mother.  Then weep away.  For there are worse things than death, and places the mind, in the throes of dementia, can descend to where even love can no longer reach it.

“The Father” is extraordinary storytelling helped immeasurably by Hopkins’s gentle, delicate performance.  One can’t help but regard his Anthony, this old man, as a helpless little boy—perhaps one even living at the heart of all those layers Hannibal Lecter might have built to protect himself.  In the end, facing the end of it all, Anthony cannot even properly process the full measure of his own life.

So what, then, for the rest of us?  To quote the late Warren Zevon, facing terminal cancer, “Enjoy every sandwich.”

“The Father” opens in theaters and on demand Friday. 

Olivia Colman in “The Father”