I am sure that anyone who has ever engaged in the act of creative writing found the multiple layers of truth in that statement, and stood back to wonder if God really had this much fun for his creations, no matter their background, and for a moment must have felt that overpowering sense of both absolute power and unselfish love of one's characters, and for a moment, really tasted what the experience of the Divine must have been. It's what makes the act of creation addictive at the bottom of it all.
Ruby Sparks takes that premise and makes it literal: with its premise of a writer who writes a girl who has existed in the recesses of his subconscious into existence, and is suddenly made aware of the Godlike power that he wields over this one individual, and tells a coming-of-age experience in how his progression of a selfish and possessive love that seeks out only ideas rather than people, to reaching the selfless, uncompromised love that all great creators should share allows him to deal with reality and realize his inadequacies in life.
The writer, Calvin Weir-Fields is played by constant straight-man Paul Dano and his career has been in a lull since he wrote his most well-known novel out of high school and has since been handled a windfall on a platter. Weir-Fields though has only published short stories since and is looking for his next big hit, both professionally and in his almost nonexistent love life. However, he has been getting visions from his subconscious in his dreams, that of a mysterious woman who has been speaking to him. With that inspiration, he creates his dream girlfriend: the Dayton, OH-born artist Ruby Sparks (Zoe Kazan).
It is not long before Ruby comes to life in a manner that is never explained and doesn't require any. Like similar thought-experimental fantasy comedies, the fantastical solely happens as an excuse for the main character to be tested in a manner that allows him to outgrow his limitations and to introduce a whole set of quirky characters onto the screen. Ruby isn't written very deeply nor very well, which is just as well because she's meant to be a reflection of her creator's callow and idea-obsessed personality and fittingly never achieves anything beyond the rudiments of a few personal traits that Weir-Fields feels fit soon to alter as he sees fit. The supporting cast are all game, from Annette Bening as Calvin's neo-hippie mom and Antonio Banderas as her lover to British comedian Steve Coogan as Calvin's rakish mentor.
Jonathan Dayton and Valerie Faris of Little Miss Sunshine offer smooth direction, but Zoe Kazan's screenplay remains a witty but generic piece of work, really lacking in ambition even compared to the likes of Groundhog Day (probably the benchmark of such comedies) or even the now-forgotten Delirious (John Candy is a soap writer who finds himself becoming a character in his TV show), it eventually boils down towards a simple, 'if you love someone set them free' message, but delivered without much daring or even much in the way of imaginative speculation (it's mentioned that Ruby had a high school teacher, so by the film's logic it should be possible to write him to life too, but the movie never does), it ends up in fact delving very little either into the intricacies of the creative process nor the frequently intriguing permutations of the relationship between creator and creation, it's lightweight and easy, but never absurd enough to fulfill the promise of its premise.