The universe is defined as the set of all things real and imaginary. A set of class circle is the definition of a set of imaginary things called circle. A circle is a thing having all of its points (of zero area) equidistant from an imaginary center. The universal set of circles is created by this definition of a circle. Not by the instantiation of a circle. A circle's nature is created by its definition. Therefore all "true" circles are "perfect circles". A "real" instance of a circle may only approach the definition of a circle as closely as physical laws and uncertainty permits. As such, it is the nature of space-time which has defined the nature of a circle.
Any instance of a circle will be a "true" instance if it works well enough for the purposes for which it is instantiated. We have created a model of a circle, defined within the "real" universe (i.e. physical universe as defined by the topology of space-time), as a closed figure created upon a single plane by a line (which is defined as having no thickness) created by the formula a^2 = x^2 - y^2 where a is the radius. You may create a square (a quadrilateral of four equal lines constructed upon a plane having the opposing sides parallel) and call it a circle and it will be a "true" model of a circle if it provides an adequate model of a circle for the purpose for which you construct it. It is of course possible and correct to create an imaginary alternative universe where space-time is so defined that the formula for a circle is y=mx^2+c. Such an alternate imaginary universe will no longer map to the "real" universe in which we live.
PI is defined as the circumference over the diameter of a "perfect" circle, not as circumference over the diameter of an instance of a circle or even as a result of our model (a^2 = x^2 - y^2) of a circle. PI is a consequence of the definition of a circle as a thing having all of its points (of zero area) equidistant from an imaginary center - which in turn is a consequence of the universe within which that circle is defined. Q.E.D.
> -----Original Message-----
> From: firstname.lastname@example.org
> [mailto:email@example.com]On Behalf
> Of Richard Brodie
> Sent: Friday, May 14, 1999 4:02 PM
> To: firstname.lastname@example.org
> Subject: RE: virus: maxims and ground rules and suppositions
> Really, though, Pi has nothing to do with the universe. It
> has to do with
> math and geometry. There are no perfect circles in the
> universe. It's a way
> we have of describing our models.
> Richard Brodie email@example.com
> Author, "Virus of the Mind: The New Science of the Meme"
> Free newsletter! http://www.brodietech.com/rbrodie/meme.htm