The two candidates running for lieutenant governor of Virginia, both 33, both tall, brown-haired, and good looking, both attired in conservative business suits and speaking in gently modulated tones, demonstrated in a debate here today that their differences are largerly ones of style rather than substance.

In answers and comments at Hampden-Sydney College, Democrat Charles S. Robb tended to give long-winded legalistic answers to virtually any question, while Republican A. Joe Canada often produced the reverse, a simplistic response to a complicated question.

Take their positions on collective bargaining for public employees: Canada is flatly against it; Robb, who started out by saying that he and Canada held almost identical views on the subject, said "I have stated I am opposed to collective bargaining for public employees in the traditional sense, however, I think there are some very legitimate needs and aspirations of public employees that have nt been addressed and not been met. I think it is incumbent upon us to instruct or be responsive particularly on the local basis to a communication system in which the both sides can talk freely and they can voluntarily enter into an agreement as long as they insure there is no possibility of work stoppage or work slowdowns."

In another example, the two men were asked for their positions on a dam project in Charlotte County. Robb said, "Without having a detailed knowledge of that particular problem, I would say that as a basic philosophical approach to it I tend to oppose of at least not want to be included among those favoring that particular type of project, particularly when the consequences will be so drastic. I haven't heard what the electric cooperatives' side of that particular story is. There are legitimate needs for additional storage capacity on the part of many hydro electric coops . . . but as for that particular project the vibes are negative."

Canada said, "I'm against it."

There was a brief moment of difference when Canada brought up what he is making a major campaign issue - the proposed Panama Canal treaties. He has issued for press releases in the last week reiterating his opposition to the proposed treaties, which he says will have a detrimental effect on Virginia's ports, and its coal industry. He says that freight rates will go up and Virginia will thus lose business.

Robb added to his previous "cautious support" of the treaties by pointing out that both President Carter and former President Ford, the joint chiefs of staff and conservative columnist William Buckley support the treaties.

"I don't mind talking about the Panama Canal day in and day out. But what are we going to do about it," said Robb in a rare moment of almost imperceptible exasperation. "The important issues are the ones we might have an opportunity to vote on - like the ERA or pari-mutual betting."

Robb is for both; Canada wants a referendum on the Equal Rights Amendment and other "emotional" issues.

Canada, who is a graduate of Hampden-Sydney, which was founded in 1776 and describes itself as the oldest all-male college still in existence, chided Robb for getting lost on the way to the debate. "I don't need a road map to find Hampden-Sydney," Canada said. He used Robb's lack of familiarity with local roads as a way of hitting the Democrat for his relatively short political career in Virginia compared with Canada's six years as a state senator. Previously, Canada likened a Robb lieutenant governorship to getting into an airplane with a pilot who does not know how to fly.

After the debate a woman was overheard to say to her neighbor, "I think Robb has a more reasoned, rational approach."

On the other hand, a coed from neighboring Longwood College said she thought Canada "had knocked Robb under the table." She asked why. "I like his viewa and stuff," she said. Which views? "Well, you know, the way he said things."

College president Josiah Bunting III closed the forum by quoting Edward Gibbon's characterization of diplomacy and warfare in the 18th century as "temperate and indecisive."

"As someone who's just come from New York this debate seemed temperate, courtly, honest, and above board," Bunting said.

Later Bunting was asked by reporters what his impression was, as a newcomer, of Virginia politics. "I'm having a hard time telling where they're coming from," he said in genuine amazement. "Canada says he's a conservative, but he's for a popular referendum on an emotional issue. That's a staggering thing for a conservative to say. By the way, do you know who won the mayoral primary in New York?"