Joseph Jordania suggested that the ability to ask questions could be the crucial cognitive threshold between human and ape mental abilities.

But looking to the future, many Indians say they believe that the United States has crossed a crucial threshold that could herald much wider military cooperation.

He added that if the assemblage point moves beyond a crucial threshold, the world vanishes; it ceases to be what it is to us at man's level.

But there can be little doubt that television will cross the crucial threshold of resistance.

"A crucial threshold has been crossed, if it's true," Mr. Krepon said of Pakistan's declaration about fitting its missile.

Yet all these concerns seem inadequate to explain why the I.R.A. has crossed a crucial threshold.

If that proportion holds for Detroit, the city will be credited with a population of more than a million residents - a crucial threshold.

"Unless you crossed some crucial threshold," Dave Rucker said quietly.

You ignore this and then speculate that the I.R.A. "had crossed a crucial threshold," that is, seeking to kill and maim innocent people.

Yet in retrospect I see that by making the transition from merely looking at maps to inventing them, I had crossed a crucial threshold.