alt Hacker NewsI don’t think there’s a hard line. Nematodes will react to being touched, that implies a primitive level of self-awareness. Most animals possess some form of proprioceptive sense, against, a form of self awareness. Higher self-awareness is just about being able to predict and plan your own actions a few more moves ahead.
Not that I necessarily disagree, but it's easy to build small mechanical devices that react to being touched, so that alone doesn't imply self-awareness. As you go to smaller and smaller organisms, they start to more closely resemble actual mechanical(/chemical) devices.