Why do twins who look same end up having totally divergent paths?

Theory of reincarnation + theory of karma explains why twins lead totally different lives. The subtle body (emotional mind + rational mind + memory + ego + senses + prana) leave the physical body at death and look for a suitable new body to fructify their vasanas (desires). The theory of karma says that they get a new body (human, animal, plant, insect....) based on their karma - how well they have fine timings their mind. This is the only logical explanation that I have come across!