It is one of these events which – like the cloning of Dolly – change everything and nothing. As a proof of concept, the creation by Craig Venter et al of a bacterial cell controlled by a chemically synthesised genome is definitive. For the first time an organism exists that got its genome not from the direct replication of another organism's, but from a description of another organism's, stored in a computer – and slightly modified, at that, to include a distinguishing "watermark" that might as well be, and perhaps already is, a trademark. It's also a landmark. This is a moment in evolution, the origin of a new kingdom: the Synthetica, as artist Daisy Ginsberg has suggested we call it, supplementing nature's bacteria, eukarya, and archaea.

It's a tremendous achievement of human ingenuity and skill. And there's something wonderfully confirmatory of mechanistic materialism in the building of a genome from chemically synthesised molecules, that genome running a cell, and that cell replicating to a point where no trace of the original cell's cytoplasm is left in its descendants. This lays to rest, with a satisfying finality, the ghost of vitalism – the spooky, whiffy doctrine that there is some essence of life not captured by "reductionist" biochemistry.

On the other hand, vitalism isn't a doctrine of any major faith, besides new age theosophies and other forms of muddled thought. In my teens I caught the virus of vitalism from reading Arthur Koestler's The Ghost in the Machine – and was cured of it, ironically enough, by a creationist tract that extolled the wondrous complexity of cellular machinery: complex and wondrous enough, I realised, for life to need no other explanation. That tiny machine didn't need even the tiniest ghost.

Synthetic life, then, creates no problems even for creationists (after all, it's intelligently designed!) let alone more sophisticated theists. This won't, of course, spare us the usual TV studio parade of clergy (why them?) asked to comment – though they may find it easier than usual to give answers less stupid than the questions.

More significant than the clerics are their secular successors, the ethicists – paid to worry so we don't have to. They're already on the case. Some conjure a scenario where synthetic organisms to which there's "no natural resistance" run amok. This seems misconceived. The biosphere comes up with natural resistance to entirely new organisms every day. Unless deliberately designed for survival, synthetic organisms that are released or escape into the wild will shortly be another organism's lunch. Then there's the "playing God" objection. Professor Julian Savulescu of Oxford talks darkly about "creating artificial life that could never have existed naturally". He says that like it's a bad thing. For Venter, of course, it's the whole point.

But there are no new ethical problems here. Humanity has been playing God with animals and plants since the invention of agriculture, and our domesticated species are already the most prevalent (of their kind) on the planet. Venter has, in a neat reverse application of the precautionary principle, promoted bioethical debate about each step of his programme well before he carried them out. The dangers – of bio-error or bio-terror – may be great, but not in principle greater than those posed by natural organisms put to evil or casual use. The potential benefits, by contrast, are greater in principle. This at least is the conclusion that the United States regulatory authorities have reached. Their reasoning should not be taken uncritically, but neither should it be dismissed with a "They would say that, wouldn't they?"

Just as this synthetic bacterium is the first of a new kingdom, synthetic biology is a new way of dealing with the natural world, as radical an invention as those of agriculture or machine industry. In time it could replace both. The potential goes way beyond bacteria that can synthesise fuel or vaccines, or eat up oil spills – applications, useful though they would be, that all sound like what someone thought of off the top their head. Every foodstuff we eat could be produced by organisms designed from scratch for the purpose – as could every fibre we wear, every floor we walk on and roof we shelter under. The possibilities outstrip our imagination.