Philosophically, '1 + 1 = 2' sparks debates about the nature of mathematical truth: Is it discovered or invented? Platonists argue that mathematical entities like numbers and operations exist independently of human thought, in a transcendent realm, waiting to be discovered. Constructivists or intuitionists, however, contend that mathematical objects are mental constructs, brought into existence by human activity and proof. Immanuel Kant famously considered '1 + 1 = 2' a 'synthetic a priori' truth – synthetic because the concept of '2' is not contained within '1 + 1', requiring a constructive act of mind, yet a priori because its truth is known independently of experience.