 These issues lie at the frontier of psychological and philosophical research. The key point for present purposes is that there are two options for halting the regress of language learning: we can say that thinkers acquire concepts but do not learn them; or we can say that thinkers learn concepts through some means other than hypothesis testing. Of course, it is not enough just to note that the two options exist. Ultimately, one must develop one’s favored option into a compelling theory. But there is no reason to think that doing so would reinitiate the regress. In any event, explaining concept acquisition is an important task facing any theorist who accepts that we have concepts, whether or not the theorist accepts LOTH. Thus, the learning regress objection is best regarded not as posing a challenge specific to LOTH but rather as highlighting a more widely shared theoretical obligation: the obligation to explain how we acquire concepts.