The same fertile ground also produced a famous set of puzzles that have challenged thinkers for centuries. These are the paradoxes of Zeno. In the Dichotomy Paradox, Zeno argued that a runner can never reach the finish line on a straight track. The logic is simple. The runner must first cover half the distance to the goal. Once there, he must still cover half of what remains. After that, he must cover half of the new remainder, and so on, and so on. At each step, some distance remains. In Zeno's telling, the runner is never able to reach the finish line.

US?Iran talks follow the same logic. Washington and Tehran have broadly agreed on the outline of a deal: a 60?day ceasefire extension, a reopening of the Strait of Hormuz, and a trade of sanctions relief for nuclear constraints. Officials on both sides also describe an agreement as imminent. Yet each apparent breakthrough produces a new obstacle. Negotiators still haggle over language, sequencing and enforcement, and have even yet to settle the basic question of who signs first. Like Zeno's runner, the two sides keep halving the distance to a deal – closing in on it step by step – without seeming to ever arrive.

The resolution to Zeno's paradox lies in the concept of limits. So when will President Trump and Ayatollah Khamenei reach theirs? When is enough, enough? Markets still assume that moment is close, with the front?month Brent contract hovering just above six?week lows. But the longer Washington and Tehran fail to reach an agreement, the more they open the door for disruptors to shape events, from US?Iran skirmishes in the Strait of Hormuz to Israeli strikes in Lebanon.

The past 24 hours indeed showed how fragile this equilibrium is. Iran's IRGC?linked Tasnim agency reported that Iranian negotiators would halt talks with the US in response to Israeli attacks in Lebanon against Hezbollah. It also warned that the "resistance front" could be activated, including potential Houthi involvement in the Bab al?Mandeb Strait. Oil prices jumped 7%, the dollar strengthened, and equity futures turned red. Within hours, however, Trump said he had spoken to both Hezbollah and Netanyahu (all while saying he "really doesn't care" if talks collapse) and claimed that Israel and Hezbollah would stand down. He also added that talks with Iran were proceeding at a "rapid pace", a line we have now heard for weeks.

Oil prices quickly reversed, but scepticism is warranted. Trump again appears to negotiate with himself. He claims progress while trying to contain escalation on fronts he does not control. From Tehran's perspective, that urgency weakens the US position. Why offer concessions that fall short of core strategic interests if they believe they can roll the US president a bit further? The past day suggests Iran does not see itself as the side under decisive pressure. It appears to believe that the US and its partners have at least as much at stake in avoiding further instability. In that setting, President Trump does not seem to hold the stronger hand. And while Zeno's runner never arrives, the real world does have real limits, and we are moving steadily closer to physical supply hitting effective tank bottom.

It cannot be stressed enough: the longer this drags on, the bigger the problems become. The PMIs made that clear yesterday. The US manufacturing ISM rose to 54, its highest level in four years, but that headline is deceptive. Much of the strength reflects companies bringing forward orders and activity to build inventories and protect against supply chain disruptions. That boost is likely to prove temporary but inflationary.