Many of us giggled and grinned as, on our way into a marathon expo, we passed an exhibit above which a banner dared one and all to “Run Like an Ethiopian.” Under that banner, one fit city dweller stood on a treadmill, at the ready, his waist fitted with a belt attached to a sling strung up to a mini-crane arm. In front of him a flat screen displayed a virtual race course.

“Ready?” the operator asked.

The eager runner nodded. In another 20 seconds, the treadmill hummed to a 4:40 minute per mile pace. For the next 30 seconds, the runner kept up. The treadmill sped up to 4:30 per mile pace, the rate at which an elite marathon runner can chew up distance… for 26.2 miles!

The runner’s face turned red and his breathing grew labored. With determination, he pumped his arms. To his credit, he maintained his stride in some semblance of proper form for another two minutes before his feet came off the treadmill and the safety sling pulled him up to safety.

His sweaty, valiant — and failed — attempt should serve as exhibit A to demonstrate the difference between equal opportunity and equal outcome. The latter does not pass the giggle test when you dare to pretend you can run like an Ethiopian. Everyone has the opportunity to try it, but few can run one mile, much less mile after mile at a scorching pace to finish a marathon in two hours and ten minutes. The winning outcome happens for only a select few.

Is this unfair? Inequitable? Is it wrong that even top women marathoners can’t match this pace (at least as of this writing) over the entire course? No one would say so with a straight face.

Yet, our leftist progressive friends would have us believe that equality of opportunity is not sufficient. We must also demand and produce equality of outcome. We must guarantee and enforce it. This may seem reasonable. We should be able to measure, one could argue, whether we have true equal opportunity by the outcomes we achieve. If we don’t get equal outcomes, then opportunity isn’t really equal or relevant.

We can all agree on this: to the extend that equal opportunity does not yet exist for all, we should work to correct the situation. A level playing field, though difficult to achieve, is a worthy project. But equal outcome?

Think back to that treadmill. We all had equal opportunity. We could all step up and run our hearts out. But few if any of us had the slightest chance to succeed. Some of us (me!) had the good sense to not even try. No external forces, no additional preparation, and not even a targeted government program would have made any difference. For most mere mortals, the failed outcome was baked in.

This is hard to admit. Hard to swallow. It holds the potential of envious bitterness. That I should never be able to collect the big paycheck of an NBA superstar or a Fortune 500 CEO — how can this be fair, equitable? Or that a high school teacher’s yearly salary won’t match that of an engineer or a lawyer — how can that be fair or equitable? And why shouldn’t we bemoan the fact that a highly trained marriage counselor makes less money than an enterprising real estate agent or–gasp!–a divorce lawyer?

This is, however, in a nutshell, how many leftist progressives frame the issue. Many of their grievances follow this pattern, including especially the championing equal pay for women, or the comparison of financial status among socioeconomic groups. But if individuals of varying abilities, preferences, and inclinations can’t all perform at the same level, how can we hope that entire groups will succeed in such a manner?

In life, the best we can strive for is an equal chance to step up to the start line. What happens in between, and who breaks the tape at the finish line come with no guarantees. Let us then stop pretending we can all run like an Ethiopian. It doesn’t pass the giggle test.