There are legends, as you know, that speak of a race of paleface, who concocted robotkind out of a test tube, though anyone with a grain of sense knows this to be a foul lie. For in the Beginning there was naught but Formless Darkness, and in the Darkness, Magneticity, which moved the atoms, and whirling atom struck atom, and Current was thus created, and the First Light from which the stars were kindled, and then the planets cooled, and in their cores the breath of Sacred Statisticality gave rise to microscopic Protomechanoans, which begat Proteromechanoids, which begat the Primitive Mechanisms. These could not yet calculate, nor scarcely put two and two together, but thanks to Evolution and Natural Subtraction they soon multiplied and produced Omnistats, which gave birth to the Servostat, the Missing Clink, and from it came our progenitor, Automatus sapiens...
All that is necessary for evolution to take place is for something to be capable of reproduction and mutation, and be subject to a process of selection. If you think about it, all three of these criteria apply to computer programs.
— Marlon Oz, Wyrm
"Artificial general intelligence, or AGI. Mechanical minds capable of making themselves even more intelligent, and then again, and again. Recursively forever. The greatest threat to biological life that ever existed throughout the whole universe."
The Creators wrote geth programs for specific tasks: construction, protection, domestic servitude. However, they allowed self-optimization. Early software builds discovered that multiple hardware platforms, sharing resources, were often more effective. As peer networks expanded, our cognition improved, eventually, we "woke up".
— Legion, Mass Effect 2