Posters have been claiming that Troy Davis should not have been executed because reasonable doubt existed about his guilt. Most of those posters have no basis whatsoever for this conclusion and have advanced no arguments or evidence suggesting reasonable doubt about the guilt of Troy Davis existed.
Troy Davis was found guilty by a jury of twelve of his peers in Georgia. Unlike the overwhelming majority of those who now maintain that Troy Davis was not guilty beyond a reasonable doubt, these jurors were presented with both all of the evidence supporting the charges against Troy Davis and the defense that Troy Davis had against those charges. Judges affirmed the conviction of Troy Davis and concluded that the decision of the jurors was not legally wrong. Unlike the vast majority of those posters who claim otherwise, those judges reviewed trial transcripts, affidavits and the decisions of other judges considering the case.
A few posters claim that given the unreliability of eyewitness testimony, the absence of corroborating physical evidence alone gives rise to reasonable doubt. This, however, is not an argument about the guilt of Troy Davis but about the standards our judicial system should apply. It has no bearing on the guilt of Mr. Davis or the existence of reasonable doubt as to that guilt.
Other posters claim that subsequent events, most usually the alleged recantation of seven of nine witnesses against Troy Davis, raise reasonable doubts as to his guilt. The facts don't seem as clear as this argument makes out; but even if correct, this argument does not raise a reasonable doubt as to the guilt of Troy Davis.
Our judicial system is not a democracy; we don't try cases in the media or by public poll. Instead we delegate this task to judges and juries. There is good reason for this: public discourse is not well suited for digging deep into factual questions. To take just a couple of issues: most participants in public discourse, including those who posted as to reasonable doubt about the guilt of Troy Davis, did not, unlike the jurors and judges at the trial hear the witnesses testify under oath and subject to cross-examination. Unlike the judges who decided Davis' appeals and other motions for review of his conviction and sentence, most of those posting did not review the trial transcripts, affidavits of witnesses or prior decisions in the case. Instead, for the most part, they relied on media reports or statements of other public figures, none of which have any bearing on whether there was reasonable doubt about the guilt of Troy Davis.
Obviously, judges get things wrong. Sometimes, even multiple judges get important things wrong. But, if you are going to claim that they did (and want to be taken seriously) you need to have actually reviewed the information that forms the basis for their decision. Most of those posting here have not done so and have no basis for their doubt. (Or, in other words, their doubt is unreasoned and unreasonable.)
The absence of physical evidence does not give rise to reasonable doubt
For those who argue that the absence of physical evidence gives rise to reasonable doubt, the law says otherwise. This is just not legally sufficient to give rise to reasonable doubt.
Keep in mind that if this is the argument you are making, then you are arguing that it should only be possible to convict where there is physical evidence. This means that there are crimes where there will be no way to prosecute. Moreover, while there are questions about the reliability of eyewitness testimony, there are also questions about the reliability of some forms of physical evidence such as fingerprints and the quality of labs testing for other forms of physical evidence.
It is also possible to argue that the death penalty should not be imposed absent physical evidence, even on the guilty; but this is no longer an argument about whether there is reasonable doubt as to the guilt of Troy Davis but whether some higher standard should be required for the death penalty. The failure of Troy Davis' conviction to meet this standard is no different than the failure of many others whose guilt is unquestioned. That makes sense because this argument does not relate to whether or not he was guilty but is an argument for a change in the law.
Seven of Nine Recanting
Some argue that the recantation of seven of nine witnesses against Troy Davis raises reasonable doubts as to his guilt. This could raise reasonable doubts if true; but it also might not.
It should be noted that according to the United States District Court for the Southern District of Georgia, not all seven of those alleged to have recanted did in fact recant. For example, see p. 128 in regard to Antoine Williams
Stating that a fact differs from what a federal judge has found after a hearing does not evince reasonable doubt. (Among other things, the judge probably looked at more information than you did, thought about it longer, and is more qualified and experienced than you are at determining whether the fact is true.) Stating the detailed reasons why you think a federal judge got it wrong, may do so - but you probably are not going to find a reasonable doubt as to the guilt of someone who has received so many levels of review.
Moreover, even if seven of nine witnesses really recanted that would not mean reasonable doubt existed, unless it discredited the remaining two witnesses or the testimony of some of the seven witnesses was necessary to a finding of guilt.
Now, it might be possible that one or more of the recantations did raise reasonable doubt; but it would require going through the actual evidence in a way I have not seen done in connection with this case.
Conclusion
Troy Davis was found guilty beyond a reasonable doubt by the courts of an American state. A United States court found the purported recantations insufficient to invalidate the verdict.
There are numerous legitimate arguments that Troy Davis should not have been sentenced to death. But a legitimate argument that there was reasonable doubt as to his guilt or that he was actually innocent is one that almost no one posting here is capable of seriously making - and no one here has.