Metaphysics is usually associated with that part of the philosophical tradition which asks about "last things", questions such How many substances are there in the world? Which is more fundamental, quantity or quality? Are events prior to things? Or do they happen to those things? While he wasn't a philosopher, Shakespeare was obviously interested in "ultimates" of this sort. Instead of probing these issues with argument, however, he did so with plays. Shakespearean Metaphysics argues for Shakespeare's inclusion within a metaphysical tradition that opposes empiricism and Cartesian dualism. Through close readings of three major plays- The Tempest , King Lear and Twelfth Night -Witmore proposes that Shakespeare's manner of depicting life on stage itself constitutes an "answer" to metaphysical questions raised by later thinkers as Spinoza, Bergson, and Whitehead. Each of these readings shifts the interpretative frame around the plays in radical ways; taken together they show the limits of our understanding of theatrical play as an "illusion" generated by the physical circumstances of production.
A charming set of essays reading (anachronistic) philosophical concepts into Shakespeare. Whitehead is read into Twelfth Night, Bergson into King Lear, and Spinoza into The Tempest. Alternatively you could read Deleuze into the whole trio; process, intensity, and monism are blurred together under the heading of "immanence".
The textual evidence for Shakespeare's thinking on these topics is strong. Viola really does obsess over the timing being ripe for particular occasions to manifest. In Lear, there really is a preoccupation with number and measure that becomes more evident as Shakespeare revises the text. Plus, the division of the kingdom is a great example of a seemingly quantitative decision that nevertheless cannot be truly understood without its qualitative implications. And the motif of sound on Prospero's island does blur the line between performance and audience.
I was hoping to find more historical evidence of how Shakespeare actually may have come across these ideas- there is an axis of reading going from Epicurus - Lucretius - Montaigne - Shakespeare. It's not really the point of Shakespearean Metaphysics to provide a complete treatment of the subject, but it's a thought-provoking and informative adventure.