Convictions based on the testimony of a single eyewitness are starting to get questioned in the light of recent episodes of witness error. Errors are likely if an apprehended person looks similar to the criminal seen by the witness at the time of the crime. How does the human brain recognize another man? It is a very difficult question to answer. What registers in the brain when we see another person is not understood. A formal view is that if two different people share the same feature in many distinct physical attributes, then they are supposed to look ?alike?. The combination of the different features along the different attributes make this a multinomial allocation problem, with a huge number of cells, and perhaps a huge number of balls (i.e., people). This is a type of a birthday problem. We will discuss the birthday problem, the connection of the testimony issue to this birthday problem, see quite a bit of computing, and some mathematics (basically central and local limit theorems). We will try to make some general conclusions on the wisdom of convictions based on an eyewitness testimony.