The fact that we haven't explained abiogenesis does not negate the fact that it occured.
Abiogeneis is impossible. You would need far more time than the age of the cosmos and far more matter than is contained in the cosmos to get anything viable. Most folk don't understand that.
We are here for a reason.
There is no need to debate it either; all one need do is sit back and watch as new discoveries come to the fore.
We need to get used to being alone.
Neil, I respectfully disagree. For the past five semesters it has been my unhappy duty to teach undergraduate engineering majors Thermodynamics II, and we occasionally handle this problem of life and self organization of matter as a bonus problem or mini-project. I will skip the mathematical description for now and say that what distinguishes life from non-life is its self organizing orderedness (as a measure of both entropy and its enthalpic content) and reproduction. It is bounded very much by the enthalpic curve. Of course, the universe has many pockets of low entropy. Consider a star for example. Eta Carinae represents an extreme measure of orderedness but it does not reproduce. One reason why serious astrobiologists who understand some of the physical sciences and thermodynamics are optimistic about the possibility for simple life on other worlds (meaning prokaryotic life = bacteria) is that prokaryotes represent a fairly low amount of orderedness (their enthalpy content is fairly small). Which means that since we see many pockets of high orderedness in the universe, it seems likely we will find simple life in many places. This is also true in our best detailed estimates of catalytic RNA type processes which are the probable methods by which life arose around 3.8 billion years ago. So, as to your concerns, current supercomputer simulations show that rather than being a very, very rare event, abiotic life processes leading to simple cells should actually be pretty common.
As to the question Ian is asking about Earth like worlds, that is very much harder to guesstimate. The reason is that once very simple prokarya evolved, the best evidence indicates that the next 3.2 billion years life continued to remain one celled (either as prokarya or as eukarya starting perhaps 1.5 BYA). This makes sense because for life to assume mulit-cellular organization, it must make a huge jump up in orderedness. This is thought possible if a star begins putting out more light than in past epochs (the sun grows about 10% more luminous every 900 million years) or an exothermic window is opened (such as the build up of oxygen around 600 MYA). Because of these possible conditions, Earth underwent a very strange and still unexplained explosion of life over a very short period of time (the Cambrian Explosion). (and that has never been repeated since) Life exploded onto the scenes from simple single celled eukarya and simple colony forms to true multi-cellular forms of many different body plans. Because this represents a much more ordered state, this means the pockets of enthalpy where this exists are likely to be less.
And finally, in the quest for Earth like worlds and possible ETs, consider that most university educated professional biologists estimate that 99 to 99.9% of all life that ever lived is now extinct. If we assume the lower bound, then this means that if Earth currently holds about 10 - 15 million species that there have been about 1,200,000,000 species that have lived on Earth. (although, remember, only perhaps 400 to 500 million of them eukarya) (also to be fair, some biologists believe that Earth has held up to 750,000,000,000 species). Since natural selection pressures have only given rise to sapient life once (or possibly a few if you consider dolphins, chimps, etc...) out of hundreds of millions of environments, then we have a very, very strict bound on high ordered intelligent life developing.
And that is the reason why many serious professional scientists from the physical sciences who hold a doctorate estimate that bacterial like life out among the stars is probably pretty common. Worlds where you have simple eukarya like colonies may also be fairly abundent. But worlds with six legged horses and intelligent exosaurs might be very rare.
Time will tell, my friend.