Science can explain only so much. When science fails, we can remember that, as Henry Miller said, “Every man has his destiny.” And every woman hers. And in the case of “Just Like Heaven,” every couple theirs.

Reese Witherspoon and Mark Ruffalo star in “Just Like Heaven,” a film that questions science’s hard facts and reminds us, gently, about the powers of faith and love.

Elizabeth (Witherspoon), a workaholic doctor with no time for a personal life, is left in a coma after a car accident. David (Ruffalo), whose wife died two years earlier, sublets Elizabeth’s apartment based on the quality of her couch.

But Elizabeth still lives there – sort of. It turns out that she’s neither here nor there, neither dead nor alive.

After getting some clues to this (Elizabeth can walk through walls, for one), the two try to discover the truth about what happened to her, fall in love and then race against time to save her life.

Based on “If Only It Were True,” a French novel by Marc Levy, “Just Like Heaven” meshes the physical and metaphysical into a world – and an apartment.

Director Mark Waters has made a film that, like “Freaky Friday” and “Mean Girls,” has comedic moments. But in this case, he focuses more on love.

But it’s unfair to classify “Just Like Heaven” as a romantic comedy simply because there is a kiss and a couple of jokes. Instead of merely sticking to the “boy-meets-girl, (insert conflict here), boy-gets-girl” formula, it delves into the realm of faith and miracles.

And then the life support issue comes up – but almost softly, and always smartly. The film uses life support more as a plot device than a political point.

We’re asked to consider what brought these two together rather than what could keep them apart. No one knows why David is the only one who sees Elizabeth or why his touch is the only one she feels. We’re asked to trust that, although it might not be immediately clear, things happen for a reason. And, above all else, we’re asked to believe in love.

In a time when face-to-face interaction is losing ground, the most powerful scenes are the ones with a simple hand-to-pseudohand touch. Near the end of the film, when it seems he’ll lose Elizabeth forever, a desperate David seizes his first and possibly last chance for a kiss from the woman he loves. It’s the first time they truly touch, and that contact makes a deeply emotional scene.

So let the cynics scoff at the “Sleeping Beauty”-esque ending. “Just Like Heaven” shows that the romantics, who are by no means hopeless, are correct in believing that love really can conquer all. It won’t go down as the greatest love story of all time – that title’s already been taken – but it does have heart.