Levin doesn\u2019t believe this should be incendiary in any way. \u201cIf you think brains and neurons are special, you have to ask yourself: \u2018How did they get here?\u2019\u201d he said. In the yawning span of time before evolution produced the first neuron, cells found other ways to navigate their environment, \u201cdoing pretty much the same thing that neurons do, just at slower speeds\u201d. There\u2019s no reason to think that, upon the arrival of the first synapse, evolution \u2013 a notorious hoarder \u2013 would merely have wiped away the older mechanisms that had existed for billions of years.<\/p>\n\n\n\n
Which isn\u2019t to say that humans are indistinguishable from single cells, Levin pointed out. \u201cThe way I explain the continuum is with the word \u2018adult\u2019.\u201d The word\u2019s function is to smooth the business of everyday life: voting, driving, drinking, buying fireworks, joining the army. \u201cBut we all know that no great shift happens on your 18th birthday, right?\u201d Levin said. \u201cThe word \u2018adult\u2019 sweeps under the rug all the deep questions about personal responsibility, and when we acquire it, and how we acquire it.\u201d<\/p>\n\n\n\n
Many of these terms such as \u201ccognition\u201d and \u201cmemory\u201d are just like that, Levin said. \u201cThey\u2019re not sharp scientific categories.\u201d He considers putting quotes around words a weaselly move. \u201cSometimes the slime mould knows, not \u2018knows\u2019, and there\u2019s nothing scientific added by using the quotes,\u201d he said. \u201cOf course, that\u2019s not the same thing as saying it knows that it knows. So we just need to have the right words and use them carefully, and not invent new ones because we want to be special.\u201d<\/p>\n\n\n\n