The Cost of ‘Common Sense’

‘I t ain’t what you don’t know that gets you into trouble,” said Mark Twain, that brilliant purveyor of American wisdom, “it’s what you know for sure that just ain’t so.” This is so true that modern humans developed various forms of science, including economics, to help us discern what is true versus what is merely asserted. Yet all too often the rules handed down from Washington amount to assertion dressed up as “common sense.”

A case now before the Eleventh Circuit Court of Appeals throws the consequences of that trend into sharp relief. At stake is not just economic efficiency, but the rule of reason.

The Department of Transportation’s crew-size rule for freight rail mandates two-person crews on trains nationwide. The agency admits it has no evidence that two-person crews are safer than one. No data. No cost-benefit analysis. No market failure. Yet both the agency and the court have repeatedly invoked “common sense” to defend the rule, citing the proverbial as a substitute for proof. The government’s attorney, for instance, told the court that the rule is “a commonsense product of reasoned decision making.”

The unstated rationale for the rule is political: a request from organized labor, granted by the Biden administration in the aftermath of the East Palestine derailment, a 2023 accident that involved a three-person crew. Hardly a rational basis. Meanwhile, single-operator trains run safely across much of the world, aided by automation and modern monitoring systems.

Being charitable, one might say the regulation reflects a European approach where precautionary principle is king, if not tyrant, and discretion suspect. But precaution must have limits. Anticipating possible risks and what to do about them ought to be a process governed by reason, not by a fear of endless what ifs. German freight trains operate safely with one crew member. Here in the U.S., we know that far more lives are at stake aboard intercity passenger buses than on freight trains. Yet federal law does not require a second bus driver in case the first is incapacitated. Were such a rule proposed, it would likely be laughed off as bureaucratic excess or a solution in search of a problem. So where does (supposed) “common sense” take us, exactly, when it comes to rail? That seems to depend on whose ox is gored. Or rather, which union backs the ox cart.

Unfortunately, if an essentially subjective notion of common sense becomes the standard, the standard becomes arbitrary. The rule of law unjustly yields to the rule of the regulator, and America becomes what Founding Father John Adams warned it must never be: “a nation of men, not of laws.”

When agencies can invoke intuition in place of evidence, they need no longer persuade anyone. The hard work of regulation — gathering facts, testing assumptions, weighing costs — gives way to the cozy platitude of assertion. We’ve already seen rigorous cost-benefit analysis give way to hand-waving in many cases at different agencies (in a particularly egregious way, for instance, at the Consumer Financial Protection Bureau).

Worse, one of the circuit judges on the panel in this case seems content to play along. Early in the oral argument the judge asked, “Why can’t it draw on the idea that, sort of the common sense idea that, two people . . . make it more safe?” (And she repeated the idea later.) If “common sense” substitutes for rational decision-making in the eyes of the court, then instinct defeats the basis for adjudication: reason. This would be a peculiar new form of judicial deference to the agency in a post-Chevron world.

As Twain warned, the “things we know for sure” in politics, like the idea that “two must be safer than one,” are precisely the propositions that should require scrutiny, not deference. Policy should follow evidence, not precede it. Otherwise, we exchange deliberation for decree. And in doing so, we accept regulation not as a tool of governance but as an instrument of bureaucratic convenience.

We saw during Covid what happens when ill-conceived policy dictates science, when we were told things like lockdowns would take only “two weeks to flatten the curve” — among many other things. We must not replicate that failure in transportation, or anywhere else, and certainly not in the courts. If a rule cannot be defended on grounds more solid than “common sense,” it has no business being imposed. America has always aspired to better.