We like to think that the stem cell controversy will, sometime before mankind’s end, give us definitions we can act thoughtfully upon. We need not only verbal definitions but moral perspectives. These are thought to be static, but are not. Probably Harry Truman would not today drop a nuclear bomb on Pyongyang, though doing so might have got him a runaway re-election the next day. Matthew Scully, in his book “Dominion,” has reopened the moral question of animal (mis)treatment. Ever the descendants of the Vikings, Scandinavian explorers are pressing new definitions of acceptable voluntary death.

In the matter of the stem cells, we are asked to focus on two completely different things. There are the so-called adult stem cells, which derive from cells that would never develop in a human being. To take such stem cells and do nuclear transfer research is OK. Nobody is arguing that what you are doing is snuffing out a human life.

By contrast, embryonic stem cells harbor life unborn, so that to take these and experiment with them is seen as experimentation with human beings. The ideal is to authorize the first kind of stem cell research but to forbid the second – or, at least, to restrain it.

Now here is where confusion begins.

President Bush had said that we must not encourage the termination of life even for the sake of saving life. The premise of his line of reasoning is that to destroy an embryo in order to extract its stem cells is the equivalent of abortion.

But Mr. Bush began the dispute when, in 2001, he gave his approval to the use by biologists of 78 embryonic stem cell lines already in existence, while decreeing that this would be the end of any public subsidy to the creation of further lines. The House has now voted (238-194) to approve additional subsidies for research on in vitro embryos donated by fertilization clinics. The Senate majority leader, Dr. Bill Frist, has endorsed this bill, and President Bush has promised to veto it if it reaches his desk.

The moral confusion springs in part from the isolation from one another of the nation’s laws and practices. In some states, stem cell researchers can do certain things that in other states are forbidden.

Add to this that the president’s argument has had mostly to do with the use of public funds, but the language used has had to do with universals. If the destruction of an embryo is the destruction of a human life, how do we explain the inattention given to such destruction of life in so many states?

Moreover, there appears to be no limiting guide directed at laboratory activity that is financed privately. If embryonic stem cell research involves human slaughter, why is it not forbidden? It is a planted axiom of a free society that its citizens should be free to do as they please – provided what they please does not violate basic moral protocols, such as the one against killing innocent human beings.

The only answer that can confront these mutually exclusive postulates is the absence of a consensus. This ought not to be surprising given the absence of consensus on abortion. The forlorn embryo traceable to an in vitro fertilization is thought human only after a hard exercise of imagination. Stem cells in the tens of thousands result from such enterprises, but the public mind is not greatly exercised by their loss so long as the experimenters are discouraged from such hubris as cloning. If the voters tolerate abortion on demand (pursuant to constitutional mandate), they will not likely pause for very long over the exploitation of stem cells aimed at curing human diseases and abnormalities.

It is easy to mobilize public sentiment in behalf of advances in health for full-blown citizens, much less easy to mobilize opposition to the exploitation of inchoate human beings. What is especially difficult is – to say it in plain language – that legislators who do not see the importance in affirming life in the womb are not likely, when all is said and done, to affirm the sacredness of the embryonic stem cell.