We call things either “black” or “white” meaning they represent clear, unambiguous concepts. Something that is “gray” remains subject to interpretation. Once we enter the realm of gray, there is no certainty. There are no right answers. There are no winners. Except the sophists.

Read: Which type of vendor is best suited to advise on plan design?

I’ve written earlier about the problems with the fuzziness of the term “best interest.”

Yes, the DOL’s new rule contains that phrase, but the richer tort bar potential lies in the words “reasonable” and “excessive.” Ask 10 people to define those terms and you get 12 answers (see “‘Excessive’ 401k Fees Often in the Eye of the Fund Holder,” FiduciaryNews.com, April 26, 2016). That’s a ripe environment for some of our favorite class action attorneys.

The ultimate definitions will likely be decided in some future court case. That means any “facts” will matter less than the eloquence of the argument. That’s lawyer territory, not adviser territory. Advisers like numbers. Lawyers like words. The art of regulation remains in the domain of words. Advantage: Lawyers.

So, how do they do it? I’m not a lawyer, and I haven’t stayed in a Holiday Inn Express recently. So I’m basically a nobody when it comes to legal theory. But I am a reporter, as in “I report what other people say.” I can tell you, the simple heuristic here: “excessive” means “high fees;” “reasonable” means “low fees.”

Notice three aspects about this rule of thumb. First, the fee phrases are in quotes because these “fees” are based on qualitative measures, not quantitative measures. The second deals with the idea that “low” is better than “high.” Finally, this canon focuses solely on one dimension: fees. Let’s address each of these components and the prevailing view the might fuel future court cases.

In a world of confusing subjectivity, people seek clarity. Numbers offer the most reassuring comfort in this regard.

Wait. Didn’t I say “fees” are more about feelings than science?

Yes. But the fact is “fees” are represented by numbers, and numbers are very easy to compare. One number is always either greater than or less than another (different) number. That comparison might not have any significance, but it is as clear as a bell.

Which leads us to the issue of “high” versus “low.”

We’ve touched on this before. Are higher fees bad if they produce better returns than lower fees? The prevailing view is that high fees are bad, regardless of the any other considerations. This is obviously not definitively true, but it’s not hard to convince people it’s generally true. Together, these first two parts of the familiar heuristic represent the low hanging fruit for trial attorneys.

Yet, it is the third part that might just make the day for the defense. The truth hinges primarily on the term “reasonable.” This word implies inclusiveness. It broadens the single dimension of fees and extends it to include value. It happens to be the antidote for “high” versus “low.” It forces the analysis to look not merely at the number associated with the fee, but the value derived by that fee.

As the DOL once said about fees (during discussions concerning the 2012 mutual fund fee disclosure rule), that sometimes high fees are better than low fees. Never forget that.