Quantum mechanics was reformulated as an information theory involving ageneralized kind of information, namely quantum information, in the end of the last century.Quantum mechanics is the most fundamental physical theory referring to all claiming to bephysical. Any physical entity turns out to be quantum information in the final analysis. Aquantum bit is the unit of quantum information, and it is a generalization of the unit of classicalinformation, a bit, as well as the quantum information itself is a generalization of classicalinformation. Classical information refers to finite series or sets while quantum information, toinfinite ones. Quantum information as well as classical information is a dimensionless quantity.Quantum information can be considered as a “bridge” between the mathematical and physical.The standard and common scientific epistemology grants the gap between the mathematicalmodels and physical reality. The conception of truth as adequacy is what is able to transfer“over” that gap. One should explain how quantum information being a continuous transitionbetween the physical and mathematical may refer to truth as adequacy and thus to the usualscientific epistemology and methodology. If it is the overall substance of anything claiming to bephysical, one can question how different and dimensional physical quantities appear. Quantuminformation can be discussed as the counterpart of action. Quantum information is what isconserved, action is what is changed in virtue of the fundamental theorems of Emmy Noether(1918). The gap between mathematical models and physical reality, needing truth as adequacyto be overcome, is substituted by the openness of choice. That openness in turn can beinterpreted as the openness of the present as a different concept of truth recollectingHeidegger’s one as “unconcealment” (ἀλήθεια). Quantum information as what is conserved canbe thought as the conservation of that openness.