The argument from imperfection is one used by proponents of evolution
against creation scientists
Creation scientists believe in an conscious designer of the natural world. They point to the many examples of intelligent "design" in organisms and say that it cannot have come about by chance. Surely, they say, someone has guided the design and creation of these organisms in all their perfection. They do not believe evolution can adequately explain these perfections.
The argument from imperfection points to examples of imperfection in the natural world as evidence that there was no divine creator - any conscious designer would have done these things differently, it is said.
One example is the "blind spot" in eyes. Photocells feed sensory information back to the brain through nerve "wires". Any sensible engineer would have the nerve emerge from the rear of the photocell - but in fact, it emerges at the front, and dives backwards through the retina to the brain (the place the wire penetrates the retina is the blind spot). Octopus eyes are designed the more sensible way - why would any designer create this situation?
This example, one of many (this one is taken from The Blind Watchmaker by Dawkins) is an example of an evolutionary "kludge" that is not designed in a sensible way, but confers no particular survival disadvantage and therefore has remained. It's the principle of it that would strike any engineer, survival disadvantage or no.