No Intuition of Simultaneityby H. Poincare
Two psychological phenomena happen simultaneously in two different consciousnesses. What does simultaneous mean?
What do I mean by “a physical phenomenon which is before or after a psychological phenomenon”?
In 1572, Tycho Brahe noticed a new star. It took 200 years for the light from that star to reach our earth. That star therefore began before the discovery of America. But this statement has no meaning and is just an outcome of a convention.
How could one have had the idea of putting into the same frame so many worlds impenetrable to one another?
We should like to represent to ourselves the external universe, and only by so doing could we feel that we understood it. We know we never can attain this representation= our weakness is too great. But at least we desire the ability to conceive an infinite intelligence for which this representation could be possible, a sort of great consciousness which should see all, and which should classify all in its time, as we classify, in our time, the little we see.
This hypothesis is crude and incomplete because this supreme intelligence would be only a demigod ; infinite in one sense, it would be limited in another, since it would have only an imperfect recollection of the past;
and it could have no other, since otherwise all recollections would be equally present to it and for it there would be no time. And yet when we speak of time, for all which happens outside of us, do we not unconsciously adopt this hypothesis; do we not put ourselves in the place of this imperfect god; and do not even the atheists put themselves in the place where god would be if he existed?
Why we have tried to put all physical phenomena into the same frame?
But that can not pass for a definition of simultaneity, since this hypothetical intelligence, even if it existed, would be for us impenetrable. It is therefore necessary to seek something else.
The ordinary definitions which are proper for psychologic time would suffice us no more.
Two simultaneous psychologic facts are so closely bound together that analysis can not separate without mutilating them. Is it the same with two physical facts? Is not my present nearer my past of yesterday than the present of Sirius?
It has also been said that two facts should be regarded as simultaneous when the order of their succession may be inverted at will. It is evident that this definition would not suit two physical facts which happen far from one another, and that, in what concerns them, we no longer even understand what this reversibility would be; besides, succession itself must first be defined.
Let us then seek to give an account of what is understood by simultaneity or antecedence, and for this let us analyze some examples.
I write a letter; it is afterward read by the friend to whom I have addressed it. There are two facts which have had for their theater two different consciousnesses. In writing this letter I have had the visual image of it, and my friend has had in his turn this same visual image in reading the letter. Though these two facts happen in impenetrable worlds, I do not hesitate to regard the first as anterior to the second, because I believe it is its cause.
I hear thunder, and I conclude there has been an electric discharge; I do not hesitate to consider the physical phenomenon as anterior to the auditory image perceived in my consciousness, because I believe it is its cause.
Behold then the rule we follow, and the only one we can follow= when a phenomenon appears to us as the cause of another, we regard it as anterior. It is therefore by cause that we define time; but most often, when two facts appear to us bound by a constant relation, how do we recognize which is the cause and which the effect? We assume that the anterior fact, the antecedent, is the cause of the other, of the consequent. It is then by time that we define cause. How save ourselves from this petitio principii?
We say now post hoc, ergo propter hoc; now propter hoc, ergo post hoc; shall we escape from this vicious circle?
I execute a voluntary act
A. Afterwards, I feel a sensation
D, which I regard as a consequence of act
On the other hand, for whatever reason, I infer that this consequence is not immediate, but that outside my consciousness two facts
C, which I have not witnessed, have happened, and in such a way that
B is the effect of
C is the effect of
If I think I have reason to regard the four facts
D, as bound to one another by a causal connection, why range them in the causal order
D and at the same time in the chronologic order
D, rather than in any other order?
I clearly see that in the act
A I have the feeling of having been active, while in undergoing the sensation
D I have that of having been passive.
This is why I regard
A as the initial cause and
D as the ultimate effect.
This is why I put
A at the beginning of the chain and
D at the end.
But why put
C rather than
If this question is put, the reply ordinarily is: we know that it is
B which is the cause of
C because we always see
B happen before
These 2 phenomena, when witnessed, happen in a certain order; when analogous phenomena happen without witness, there is no reason to invert this order.
Doubtless, but take care; we never know directly the physical phenomena
What we know are sensations
C' produced respectively by
Our consciousness tells us immediately that
C'. We suppose that
C succeed one another in the same order.
This rule appears in fact very natural, and yet we are often led to depart from it. We hear the sound of the thunder only some seconds after the electric discharge of the cloud. Of two flashes of lightning, the one distant, the other near, can not the first be anterior to the second, even though the sound of the second comes to us before that of the first?