The article shows the positions that philosophers held to the relationship between a priori judgments and those judgments which are valid necessarily. Enlightenment philosophers of the 18th and 19th century, who though often in different ways, opposed the concept of metaphysics and scholastic necessity (Hume, Kant, Mill, idealists), play the leading role. At the beginning of the 20th century analytic philosophy was born. Its first leaders inherited from their predecessors an antipathy to metaphysics, and so they had no desire to return again to the traditional concept of necessity (Wittgenstein, Carnap, Ayer). Their logic and the new characterization of the a priori paved the way for the linguistic turn. Some of their followers in the second half of the 20th century realized that the concept needed to be returned to its original meaning (Kripke). This is not a mere repetition of the Aristotelian-scholastic conception, but a new addition that rethinks the relationship between the notions of a priori and necessity.