It is possible to be measured the spead of a particle at a given moment? It is possible to be measured the position of a particle at a given moment? It seems that, we should reflect first at the meaning of "at a given moment". We use this words with the intention to name a stable or fixe phase (state) of an object. That is, we suposse that an object cannot be in different places in the same time, or at a given moment, cause motion or the change of place requires time. That is, it seems that we suppose a quanta of time, an elementary unit of time, an inferior limit of time. The elemetary unit of time is still temporal, that is it still implies a minimal change. But then, if "at a given moment" represents an unchanging or stable phase, "at a given time" would have to be undertemporal or non temporal. That is why, our implicite and unclarified thought is vague and affected by oppositions. Imagine that an object moves along a stright trajectory from a spatial point A until to the spatial point B. We suppose that the pure space is a continuous and uncomposed reality. The shortest spatial distance between A and B is finite and is represented with a finite mathematical magnitude. But if we want to divide a positive mathematical magnitude, we can increase unlimitedly the divisor of that positive magnitude, but we will cannot arrive at an elementary ultimate unity. If we accept that the space is a continuous and uncomposed reality, then we cannot obtain a spatial quanta by division. But if the space from A to B is continuous, the motion from A to B is also continuous? In general the motion is continuous? If the motion, then the time is also continuous, then the motion-time also has no quanta or elementary unit, then there can be no a fundamental moment in which the object is in an individual place, but as we continue to increase the divisor of distance we divide also the time without to arrive at a quanta of time. By "at a given moment" we would suggest a fundamental unit of time and by "motion requires time" we would suppose a temporal multiplicity. If the time is continuous we would cannot observe an individual place of a particle that moves. In the last case even an individual place or an spatial quanta/point would be impossible. If the space is continuous, there can be no a fundamental atom or indivisible point of space, but any spatial quantity can be futher divided, then an absolute precise determination of the position of a particle would be not possible. Can have a spead a particle at a given moment? A particle which does not move canot have spead. There can be no spead without changing and changing without spead. If a particle can have a spead at a given moment, then it moved in that given moment and its motion has had a concrete spead. If time is not continuous, then under a limit there is no motion and changing and, therefore, there can be no spead. If we accept a conventional fundamental unit of space, then we can measure more easily the spatial and temporal quantities. Then every motion requires a spatial place difference (? place ? 0). But, when a particle is in the spatial position A, its ? place = 0, therefore it cannot have neither motion nor spead. In this special sense, I consider that, the spead of a particle cannot be determined, when it is in a precise position, when its ? place = 0, when it is outside of motion or changing. In the quantum mechanics it is supposed that if we would know the precise position of a particle, then we would not be able to determ or to predict with precision its future position, but only with a grade of probability. The actual physics have to answer many questions, but this does not mean neccessarily that the universe is irational or random. For instance, why a continuous or discontinuous microphysical entity moves at all? What are the causes and the mechanims of the motion of a microphysical particle? What are the causes of the variation of its spead? What are the causes that determ a microphysical particle to mote in an individual spatial form? That is, why the trajectory of the motion of a particle has a particular geometrical form? Why it moves in a particular sense or direction? Why its motion has an individual amplitude and an individual frequency? The previous causes are internal, external, or both? Why the electomagnetic radiations have a constant spead? Why the spead of light in vacuum is not different? What are the causes of the spead of light? I consider that, our actual ignorance does not prove that at a fundamental level our universe is random and irational. My plilosophical convictions are that: any motion should have a cause or causes, any spatial form of motion should have causes and conditions. I and the rational philosopher of science, I believe, refute the irational interpretations of the universe and instead of the Copenhagen interpretation we believe in Leibniz's principle of suficient reason in the spirit of which there can be no any occurence (eg., the motion of a particle with a particular spead and trajectory) without a suficient reason or cause. In the spirit of Leibniz's principle, there can be no an acausal motion or an acausal spatial form of motion. Leibniz's principle is superior to Bohr's irational interpretation, being a fundamental principle of the human reason. In this sense, I consider that, Einstein's creed was superior, being more rational, to Bohr's reaction: "Einstein, don't tell God what to do" which appear only as revolting an unreasonable impudence. There can be objects that are in causal relative spatial rest state. Even the existence of indestructible, if there is such a thing, sould be conditioned by its indestructibility or by the reasons of its indestructibility.