Some people at the Federal Trade Commission call Timothy J. Muris a Richelieu--the man who really runs the agency for FTC Chairman James C. Miller III.

Others regard Muris, head of the agency's bureau of consumer protection, more kindly, calling him a Sherlock Holmes who helps Miller ferret out earlier wrongdoing by the agency.

But no matter what commission officials call Muris, all agree that the 32-year-old lawyer is one of the most controversial figures in the agency--thanks to his strong attacks on previous commission policies, his sharp criticism of current commissioners, and his distrust of almost all FTC staff members who joined the commission before Miller.

Since he went to the commission with Miller nine months ago, Muris has attacked past and current commission policies, calling them irrational, unnecessary and without any justifications or benefits for consumers.

In statement after statement, Muris has made it clear that he has one mission at the FTC: to reverse more than 10 years of commission activism and keep the agency from interfering in business activities unless absolutely necessary.

"He views his mission as one to search and destroy those areas that are inappropriate for government intervention," comments Howard Vine, director of government regulation and competition for the National Association of Manufacturers.

"Rarely have I seen anyone in government attack his mission more intensely," Vine adds.

Within months of joining the FTC, Muris became the chief architect behind Miller's legislative proposals to limit the agency's ability to attack unfair and deceptive advertising.

Contending that most previous cases brought by the commission were trivial and unreasonable, Muris and Miller argued that the law needed to be changed to bar the agency from attacking any deceptive advertisement--such as a misleading product claim--unless the commission could prove that the promotion was so false and exaggerated that a "reasonable" consumer was actually harmed.

The proposals have not yet been endorsed by Congress, although Muris and Miller will press their case again this week in Senate Commerce Committee hearings.

Whether or not they are ultimately accepted by Congress, the proposals are significant because they represent the first time in the agency's 68-year history that an FTC chairman has asked Congress to reduce the commission's powers.

Now Muris also is trying to stop the commission from issuing a handful of pending industry-wide trade rules to correct consumer abuses.

Previous commission rules "have produced very little," Muris said in a recent interview. For one thing, he complained, it takes so long for the commission to consider a rule that by the time it is finally issued, the abuses may no longer be present.

"A case-by-case approach" in which the commission goes after deceptive practices by a specific company "in general can be more appropriate under most circumstances," Muris added.

But Muris opposes industry rules for an even more fundamental reason. For the most part, he says, the commission has tried to impose sweeping changes in individual industries without having sufficient evidence to justify a rule. Although the commission may have heard hundreds of anecdotes that seemed to justify the rule, he says, it did not have valid, up-to-date nationwide surveys to demonstrate that there is a problem needing correction.

As Muris recently told the four commissioners, solid statistical evidence is needed to justify action because commissioners don't have any more expertise in consumer problems "than any random group of adults selected at large."

That remark did nothing to endear Muris to the commissioners who, with the exception of Miller, have expressed strong doubts about Muris' strong evidentiary standards.

Already concerned that Muris is trying to halt individual cases because less than a handful have emerged from his office, commissioners are now fearful that Muris' new standards represent nothing less than an attempt to stop rule-making altogether.

Muris' demand "may effectively preclude promulgation of any of the trade proposals before us," charged Commissioner Patricia P. Bailey at a recent commission meeting. The demand "unnecesarily exceeds that demanded by the commission, the Congress, or the courts in the past," she added.

Muris contends that his strong standards are needed to guarantee that the FTC does not unnecessarily interfere with business. His strong dislike for government regulation, he says, grew out of his adolesence in Southern California. "People who grew up there in that time, whether they are liberal or conservative, are much more suspicious of government . . . We don't have an abiding faith in government."

Privately, however, some FTC officials suggest that Muris' views stem more from his earlier days at the commission. From 1974 to 1976 he was an assistant to the director of the agency's Office of Policy Planning and Evaluation. At the time, the office was ridiculed by most of the liberal agency officials for its conservative outlook and repeated opposition to a host of pending rules.

"One of the things that motivates him is his memory of his early days here when he was ignored and ridiculed," comments one FTC official. "Now he has a chance to get even and vindicate himself."

Whatever the motive for his opposition to government regulation, it is clear that Muris' views have made him a close confident of FTC Chairman Miller. "Their personalities and approaches are so similar and consistent that at times it is difficult to tell who is influencing whom," notes one business lobbyist.

"Tim's a rare bird," Miller said recently, remembering how he had met Muris seven years ago in an antitrust course Miller was then teaching at George Washington University. At the time, Muris was at the FTC and Miller remembers that "very frequently I was up there lecturing on the FTC while Tim was back there snickering at my kindergarten views of agency issues."

But they soon became fast friends, with Muris impressed with Miller's philosophy that less government is better.

As a result, when the Reagan administration asked Miller to head a transition team at the FTC, Miller made it clear that Muris was one of the people who had to be on the team.

He is now on Miller's permanent team--and playing a crucial, if not the leading role, in curbing the agency's powers.