“The uncertainty of the future is already implied in the very notion of action. That man acts and that the future is uncertain are by no means two independent matters. They are only two different modes of establishing one thing.The words in yellow are a gross non sequitur.
We may assume that the outcome of all events and changes is uniquely determined by eternal unchangeable laws governing becoming and development in the whole universe. We may consider the necessary connection and interdependence of all phenomena, i.e., their causal concatenation, as the fundamental and ultimate fact. We may entirely discard the notion of undetermined chance. But however that may be, or appear to the mind of a perfect intelligence, the fact remains that to acting man the future is hidden. If man knew the future, he would not have to choose and would not act. He would be like an automaton, reacting to stimuli without any will of his own. Some philosophers are prepared to explode the notion of man’s will as an illusion and self-deception because man must unwittingly behave according to the inevitable laws of causality. They may be right or wrong from the point of view of the prime mover or the cause of itself. However, from the human point of view action is the ultimate thing. We do not assert that man is ‘free’ in choosing and acting. We merely establish the fact that he chooses and acts and that we are at a loss to use the methods of the natural sciences for answering the question why he acts this way and not otherwise.
Natural science does not render the future predictable. It makes it possible to foretell the results to be obtained by definite actions. But it leaves unpredictable two spheres: that of insufficiently known natural phenomena and that of human acts of choice. Our ignorance with regard to these two spheres taints all human actions with uncertainty. Apodictic certainty is only within the orbit of the deductive system of aprioristic theory. The most that can be attained with regard to reality is probability.” (Mises 2008: 205).
It is untrue that, if a human being knew the future perfectly, then he would not act. On the contrary, a simple thought experiment suffices to show how absurd this idea is.
Imagine you knew the future without any uncertainty, that is, a perfect knowledge of the future and perfect knowledge of the consequences of your acts. Would you suddenly cease acting?
Of course not. Unless you want to die, you would continue eating. You would know what foods pleased you best and would never have the misfortunate to eat some spoilt food which would make you sick.
Furthermore, you could, for example, make all the money you ever dreamt of by betting at horse races, playing the lotto, or gambling at a casino, and win precisely because you would know what actions to take in order to win a fortune. You would, moreover, never have any serious accident because you could foresee all consequences of all actions.
Endless examples quickly multiply for why we would continue to act even if we knew the future.
And Mises is also wrong to think the reality of uncertainty is deduced from the action axiom.
How could Mises know that there are no human beings who have perfect knowledge of the future to begin with?
You cannot know this a priori. The statement
(1) no human being now or in the past has or has had a perfect knowledge of the futureis a synthetic a posteriori statement. We can establish it as true to a high degree of probability, but only with empirical evidence and inductive arguments.
For example, we have no recorded example of a human being who could predict perfectly all things in the future. Instances where people claim to know the future (as in astrology, magic or clairvoyance) are unconvincing. Frequently such people are wrong, can be shown to be charlatans, or their “predictions” when apparently true are neither impressive nor out of the ordinary in that they can be shown to be lucky guesses or deductions based on evidence they already have (think of a clever palm reader who simply guesses things about people on the basis of observation and probability).
We know from empirical investigation of human beings that they have experience of the present and memories of the past, but no memories of the future. And there is no scientific evidence that dreams, for example, foretell the future.
Modern science and biology make it extremely unlikely that any human being could know the future, and no possible scientific explanation for how this could be possible has ever been proposed.
All in all, the weight of evidence can be used to construct a set of inductive arguments to the effect that it is highly probable that proposition (1) is true.
But Mises’s action axiom cannot establish its truth. Indeed, the very idea that “all human action by non-mentally-ill human beings aims at ends and is, in this sense, purposeful” can only be proved by empirical evidence and inductive argument too.
Why? Because Mises cannot even establish a clear definition and criteria for
(1) what constitutes a non-mentally-ill human being, orwithout recourse to a vast amount of empirical scientific evidence about human behaviour, via medicine, psychology and biology.
(2) what constitutes conscious and voluntary human action in the first place
Mises, L. von. 2008. Human Action: A Treatise on Economics. The Scholar’s Edition. Mises Institute, Auburn, Ala.