What Is A Computer

Recently on Shades Of Brown, the question of "what is a computer?" came up in regards to the new iPad Pro. I went off on how input method is not the deciding factor in how much of a computer the device is. Rather what decides if a device is a computer is the ability to create and manipulate data1. My thoughts came from the dozens of discourses I've seen online about how a mouse driven GUI or a terminal are the empirical input methods for computer and anything else is lesser. For that basis is how we consider if a device is a computer and only that basis. I disagree.