This paper offers a simple answer to Wigner’s question about the unreasonable effectiveness of mathematics in the natural sciences. The central claim is that the effectiveness is not unreasonable if the physical world is informational in structure. Mathematics begins from distinction. At its logical base it works with identity and difference, truth and falsity, and in formalized settings with bivalent values such as 0 and 1. Information, in the minimal physical sense, is likewise nothing more than the ability to distinguish one state from another. If physical systems are describable as sets of distinguishable states and allowed transitions among them, then mathematics and physics are built on the same primitive act: distinction. On this view, mathematics fits physics so well because both are expressions of one informational architecture. Shannon’s formal measure of information and Landauer’s principle provide a quantitative and thermodynamic bridge that anchors this argument in physics, rather than leaving it at the level of metaphor. The paper does not require the strong claim that reality is literally a digital computer. A weaker and more general thesis is sufficient: if the world is structurally informational, then the applicability of mathematics becomes expected rather than mysterious.