In Nature I haven’t seen a true straight line. The moon orbits around the earth; so will the sun cover a cosmic year in an elliptical line. A growing plant won’t take one; neither will branches from the main stem. A marine mollusc like nautilus hates to go straight, so will an oyster. How far the expression ‘as the crow flies’ is true? (Think of our faces. If from a photograph, a composite image is made up using only half of your face you shall notice the image strikes you far stranger than you thought possible. So much for our symmetry.)
If one draws a straight line using a ruler and pencil on a piece of paper it may seem a straight line but not true: examine that supposedly straight line under an electron microscope to know what I mean. We humans can only approximate. Our ideas must similarly shape up from what we say in absolute terms.