We know they are better than they were last year, probably better enough to do what no one would have believed they could do before the start of the season, which is win their division.

But we still don't really know how good the Jets are, even with Brett Favre at quarterback, an 8-4 record and a one-game lead on the New England Patriots.

Worse than that, we're not likely to find out how good they really are during the rest of the regular season, even if they run the table and finish with the best record a Jets team has had in a decade.

Any team that can outgut the Patriots in Foxborough - in overtime, no less - and humble the Titans in Tennessee obviously is very good indeed.

But any team that can lose to the Raiders and need a last-gasp rally to overcome the Chiefs might not be quite good enough.

So much for the Jets-Giants Super Bowl hysteria that has gripped a good part of this town in the past couple of weeks.

We already know how good the Giants are, because they show us every week. They play good teams, they win. They play bad teams, they win. Guys get hurt, miss practice, accidentally wing themselves in nightclubs, they win. They have become so predictable in their excellence as to almost be boring.

The Jets, on the other hand, still are very much an unknown quantity.

There is no disgrace in allowing 34 points to the high-powered Denver offense, as the Jets did yesterday. But there is no excuse for failing to score 35 against the Broncos' miserable defense, statistically among the worst in the league.

And there is really no rational answer for how a team that just played two spectacular games in places as hostile to visitors as Foxborough and Nashville can return home and come up so empty.

"We were outplayed," said Favre, who certainly was by Jay Cutler, his Denver counterpart.

"We didn't execute," said Thomas Jones, who certainly did. His two spectacular touchdown runs in the first half and 138 rushing yards provided the only offensive highlights in a 34-17 loss that otherwise was as dreary as the weather.

"We've established a certain identity," coach Eric Mangini said, "and that was nothing close to it today."

But just what identity have the Jets established so far? Are they a very good team that just happened to have a very bad day yesterday? A maddeningly inconsistent team that fell back into familiar patterns of failure?

Or, most ominously, are they an improving but still unfinished team that, because of the anomalies of the schedule, reached its peak about two months earlier than needed?

The next four weeks may provide some easy victories, but they will not provide the answer. The rest of the season is a diet of cotton candy and french fries, momentarily satisfying but likely to leave them fat, dumb and happy heading into the postseason.

Next week, they travel to San Francisco to face the 4-8 49ers. The following week, they're home against the 6-6 Bills. Then it's off to Seattle and the 2-10 Seahawks, followed by the curtain-dropper at home against the 7-5 Dolphins.

In a sense, the Jets may be victimized by the softness of their schedule, the NFL's reward for coming off a 4-12 season. Although Mangini - as angry after the game as anyone could remember seeing him this season - stressed the importance of maintaining intensity week in and week out, regardless of the opposition, it was obvious from the first quarter that the intensity that had carried the Jets past the Patriots and Titans was missing in action against the Broncos.

"As we move forward, the games get more important, not less," Mangini said. But his hint that the Jets had had a less-than-stellar week of preparation for yesterday's game indicated that not all of his players have received the memo.

In fairness, there were some bad calls yesterday. One was by the officials, who allowed the Broncos' Vernon Fox to advance Jerricho Cotchery's "fumble" into the end zone on a play in which Cotchery clearly should have been ruled down. The others were by offensive coordinator Brian Schottenheimer, who passed up what looked like the sure bet of running Jones - who had racked up 109 yards on 12 carries to that point - on successive third-and-1 and fourth-and-1 plays in the second quarter in favor of passes that fell incomplete.

But the most disturbing aspects of the game were the inability of Favre and the receivers to shred a pass defense that is statistically indistinguishable from that of the winless Detroit Lions , and for the Jets' offense to manage more than 17 points against a team that routinely allows 27 points a game.

"We started the day in first place and we're still in first place," Favre said by way of justifying a horrendous day. "The season's not over yet, and we don't know when it will be over."

The answer is, probably a lot later than anyone could have expected before the season started.

And if the Jets continue to play the way they did yesterday, a lot earlier than it should.