Thinking allowed

Life's Solution

Life’s Solu­tion is the title of a new book by Simon Con­way Mor­ris, Pro­fess­or of Evol­u­tion­ary Palaeo­bi­o­logy at Cam­bridge Uni­ver­sity. The sub­title Inev­it­able Humans in a Lonely Uni­verse encap­su­lates what seems to be the book’s cent­ral thes­is: that on an earth­like plan­et, the pat­terns of evol­u­tion are such that they will even­tu­ally bring intel­li­gent life into being, but that there are pre­cious few earth­like plan­ets in the universe.

I plan to make fur­ther com­ments as I read the book; mean­while you can buy it here — it looks well worth a read, though it’s a fairly demand­ing work.

So far I have read the intro­duc­tion and Chapter One, so I hes­it­ate to sum­mar­ize the con­tent of the book. How­ever, Simon Con­way Morris’s hypo­thes­is seems to be that although there are poten­tially and enorm­ous num­ber of pos­sible forms that pro­teins might in the­ory take, in prac­tice the over­whelm­ing major­ity of them are non-viable; that the exper­i­ence of life on earth is that evol­u­tion will repeatedly invent sim­il­ar solu­tions to the same prob­lem, but using dif­fer­ent build­ing blocks. A clas­sic example of this ‘con­ver­gent evol­u­tion’ is the sim­il­ar eye that has evolved sep­ar­ately in octopuses and ver­teb­rates. This sug­gests that there are ‘stable’ points in the world of evolving life-forms, and that giv­en a favour­able envir­on­ment and enough time, they will be reached, per­haps repeatedly, but almost inevitably.

Taken with the sta­bil­ity of the phys­ic­al uni­verse, and the lim­ited range that the basic phys­ic­al con­stants may take to arrive at a hab­it­able uni­verse, it is tempt­ing to see that such a uni­verse is very com­pat­ible with the idea it was cre­ated in a way that would lead to intel­li­gent life.

In his pre­face Con­way Mor­ris out­lines the plan of his book, with chapters on the genet­ic code and DNA, on the dif­fi­culty of turn­ing the molecules of life into life itself, the unique­ness of the Earth, then sev­er­al chapters on con­ver­gence, and a final chapter teas­ingly entitled ‘Towards a theo­logy of evol­u­tion’. He writes ‘if you are a “cre­ation sci­ent­ist” … may I politely sug­gest that you put this book back on the shelf. It will do you no good. Evol­u­tion is true, it hap­pens, it is the way the world is … This does not mean that evol­u­tion does not have meta­phys­ic­al implications.’

Chapter One dis­cusses pro­teins, the build­ing blocks of amino acids, the role of DNA in the man­u­fac­ture of pro­teins, and the way that DNA codes the cre­ation of pro­teins enzymes. The same DNA code is used by all life on earth, and so must date back to the very earli­est phase of live on the plan­et. Yet it rep­res­ents an extremely effi­cient cod­ing scheme — a recent com­puter exper­i­ment to com­pare a mil­lion pos­sible cod­ing schemes chosen at ran­dom showed a nor­mal dis­tri­bu­tion ‘bell’ curve; the actu­al code used in all creatures on earth lies far, far to the edge of this curve, way inside the last per­cent­ile, with only one of the mil­lion altern­at­ives more effi­cient. ‘We may not only be on the verge of glimpsing a deep­er struc­ture to life,’ he writes, ‘but [also] that it mat­ters little what our start­ing point may have been: the dif­fer­ent routes will not pre­vent a con­ver­gence to a sim­il­ar end.’

Enough extracts, time to get into some more read­ing, and per­haps some more opin­ions too.