Well, that’s the claim:
In recent years, Australopithecines, a genus of early hominins, have emerged as possibly the earliest humans with indirect evidence of tool use, between 2 and 3 million years ago. The new research suggests their thumbs at this time were more similar to those of chimps than to ours.
Compared with their primate ancestors, Australopithecines had better manual dexterity, researchers say. But while their hands are similarly proportioned to modern humans, their thumbs couldn’t achieve the same extent of efficient opposition that we have today.
“Increased manual dexterity in the form of efficient thumb opposition was among the early defining characteristics of our lineage, providing a formidable adaptive advantage to our ancestors,” says paleoanthropologist Katerina Harvati of the Eberhard Karls University of Tübingen in Germany.
Carly Cassella, “Tantalizing Evidence Hints Ancient Humans Had Stone Tools Before Opposable Thumbs” at ScienceAlert
That implies that minds developed before opposable thumbs.
Those of us who have never had non-opposable thumbs might have some trouble understanding the problem but hey, we can learn.
Here’s the open access paper.