| Ludwig von Mises | The most that can be attained with regard to reality is probability. | Human Action | p. 105; p. 105 | Uncertainty |
| Ludwig von Mises | Understanding is always based on incomplete knowledge. | Human Action | p. 112; p. 112 | Uncertainty |
| Ludwig von Mises | There is in the course of human events no stability and consequently no safety. | Human Action | p. 113; p. 113 | Uncertainty |
| Ludwig von Mises | In the universe there is never and nowhere stability and immobility. Change and transformation are essential features of life. Each state of affairs is transient; each age is an age of transition. In human life there is never calm and repose. Life is a process, not a perseverance in a status quo. | The Anti-Capitalistic Mentality | p. 106 | Uncertainty |
| Ludwig von Mises | It is certainly true that the necessity of adjusting oneself again and again to changing conditions is onerous. But change is the essence of life. In an unhampered market economy the absence of security, i.e., the absence of protection for vested interests, is the principle that makes for a steady improvement in material well-being. | Human Action | p. 848; p. 852 | Uncertainty |
| Ludwig von Mises | It is a poor makeshift to call any age an age of transition. In the living world there is always change. Every age is an age of transition. | Human Action | p. 855; p. 860 | Uncertainty |
| Ludwig von Mises | One of the fundamental conditions of mans existence and action is the fact that he does not know what will happen in the future. | Theory and History | p. 180 | Uncertainty |
| Ludwig von Mises | What a man can say about the future is always merely speculative anticipation. | Theory and History | p. 203 | Uncertainty |