"Whether or not it would be possible to drive the kind of protein machinery that you see in modern cells, like an ... that makes the energy currency of life... If it were just sitting there in a in a vent, can work out whether the natural... ion gradients in these vents would be... powerful enough to drive this machine to work. ...[Y]ou need to know what are the substrates, what are... the materials that it needs to operate? Where are they coming from? What's the concentration of them? You realize that you have no answer to any of those, and then what's the product? Well, it disappears off somewhere else, as well. So how can selection act if you've got stuff coming in from some unknown place and the product leaving to some unknown place? It made me realize that cellularization is important as a way of keeping the inside in and in keeping the outside out, and so I now have problems with the idea of seeing the entire vent as a kind of a living system."