Does the threat of the death penalty deter people from murderous behavior more than the threat of imprisonment for life? We do not yet know with anything even approaching certainty whether the death penalty does or does not deter. The question is clearly empirical, and it is likely that sophisticated statistical techniques will eventually permit us an answer.
这里出现了likely，它属于possibility signal words，所以我们可以预判作者对精密的统计技术的态度其实是怀疑的，所以下文应该是往质疑或驳斥的角度写下去。而后面的文字” All statistical arguments on the death penalty are, however, excruciatingly complex and misleading.” 证明了我们的猜测。
Absolute Signal Words
These words should make the reader reject a statement unless there is strong support.
always, definitely, irrefutably, assuredly, indisputably, undeniably, certainly, invariably, without question, etc.
Probability Signal Words
These words suggest that the information may be accurate but that other possibilities may exist.
almost, probably, presumably, there is little question, etc.
Possibility Signal Words
These words suggest that the ideas are subject to debate and that there is doubt as to their complete validity.
apparently, may/maybe, possible, somewhat, could be, might, seems, likely, perhaps, seemingly, etc.