Recently, I was giving a presentation on configuration and product change management. At the end of my talk, a gentleman told me a story about his company. The company purchased two identical machines to perform the same function. One machine went into service; the other was waiting in the wings. Over time, the deployed machine had a component failure. The obvious solution was to replace the broken part with same component from the identical machine collecting dust. Unfortunately, the “new” part did not work. It turns out the two machines were, in fact, not identical.

What makes two products identical? Is it their shape? Is it what the product does, or how it does it? The question reminds me of the paradox known as Theseus’ ship.