Ideal Platonic forms don’t exist in the universe – they are the product of the human mind only.
Corollary : It was thought by Plato that all objects have an ideal form which exists within the universe and that their counterparts – real objects or “sensible things” are simply degenerate forms of these ideals. However, the opposite is true. The denegenerate form is in fact in the mind. Consider a sphere. The most perfect spheres in the universe are stars, but as we know the surface of a star is a raging torrent of ever shifting plasma. The dimensions of the star are also imperfect – stars bulge due to their rotation and so their form is less accurately constructed than the ideal sphere. Any theories we show to be “true” about a star are subject to accuracy with regard to these tiny imperfections. All physics has to work with differing levels of accuracy and approximation.
The ideal form is degenerate because the limits of the mind (in terms of raw processing power) simplify the form, in this case a sphere, into an object that has a radius, r, which is all we need to know about a sphere. If we go a step further and discount this mathematical fact about the sphere, we may even try to describe the ideal sphere as being “infinitely smooth” for example, which no “sensible sphere” could ever be. In fact most ideal objects we imagine are, in our minds eye, or when constructed mathematically in a computer, “infinitely smooth” but as we know their “real-world” couterparts are crenelated and bumpy to the tiniest levels we can perceive.
– Your Joyful Benefactor