Two small slits

About nine­ty years ago, let’s say about a hun­dred years ago, an exper­i­ment changed the con­cept of real­i­ty. Ein­stein him­self did not dare to believe it. The exper­i­ment was based on Thomas Young’s 1801 exper­i­ment, which showed that light was a wave. It is pret­ty sim­ple. Place a light source in front of an obsta­cle with two equal open­ings. On the oth­er side, on anoth­er wall, you will see a pat­tern that looks like what is pro­duced by a wave on water. When the light waves cross each oth­er, they form pat­terns, can­cel­ing out or ampli­fy each oth­er in the same way as in water, into which two stones are thrown simultaneously.

At the begin­ning of the 20th cen­tu­ry, it was real­ized that it was not so sim­ple. If we reduce the light source to a sin­gle pho­ton, the pho­ton being the ele­men­tary par­ti­cle of light, the same wave pat­tern appears on the oth­er side, which is con­tra­dic­to­ry because a sin­gle pho­ton should have passed through only one of the two slits… We deduced that light had a dual nature, both a wave and a par­ti­cle. This is already quite dis­turb­ing. Let us com­pli­cate the exper­i­ment by oblit­er­at­ing one of the two slits. The pho­ton pass­es through the open slit but no longer pro­duces inter­fer­ence. The pho­ton has become a par­ti­cle. Rough­ly speak­ing, and if I under­stand it cor­rect­ly, light is a wave when we test its wave qual­i­ty but becomes a par­ti­cle if we try to detect… a par­ti­cle. It is the type of exper­i­ment that dic­tates the result. The obser­va­tions’ con­di­tions destroy an aspect of real­i­ty to respect our desire for the result. In short, real­i­ty with­out us does not exist.

A hun­dred years ago, physi­cists began to per­ceive a uni­verse that only appears if we mea­sure it in a cer­tain way. We can cer­tain­ly think that this defect comes from our capac­i­ty to observe. It is due to the pover­ty of our mea­sur­ing instruments.

How­ev­er, the math­e­mat­ics behind these dis­cov­er­ies, of rather cold log­ic, con­firms that it is indeed here that the whole oper­ates. Man, said the ancients, is the mea­sure of the uni­verse. There is no false pride behind this state­ment. Being part of this world, our species, gift­ed with the capac­i­ty of rea­son (per­haps not all the time with suc­cess), dis­cov­ers what is because it is part of this world. There is no sep­a­ra­tion between us and the uni­verse. With­out us, the uni­verse, at least our uni­verse, is not observed. It does not exist.

The major­i­ty of physi­cists are behind the Copen­hagen inter­pre­ta­tion, name­ly that this dis­cov­ery does not mat­ter. Sev­en axioms have been put for­ward, which can con­tra­dict each oth­er, but which coexist.

One can very well con­tin­ue to mea­sure the uni­verse and obtain con­vinc­ing results. The proof, the quan­tum com­put­ers, the com­put­er sci­ence, and the Inter­net. We live with the para­dox­es inher­ent to our dis­cov­er­ies, and we do not go look­ing for the why of things. Know­ing why this is so is not the object of science.

After all, how could we live if, from one day to the next, human beings lost them­selves in philo­soph­i­cal con­sid­er­a­tions root­ed in the archa­ic intu­itions of Hin­du thought or of the Aus­tralian witchdoctor ?

There are oth­er physi­cists, few in num­ber, but still, big ones, who have nev­er been sat­is­fied with this way of think­ing. For them, ask­ing the ques­tion of “how can it be?” or “why?” should take its place in sci­en­tif­ic ques­tion­ing. They also man­age, with oth­er hypothe­ses, to describe real­i­ty by adding the dimen­sion of con­scious­ness, whether it is indi­vid­ual or uni­ver­sal (here, we speak of a uni­verse that thinks itself).

When we have reached the point where we can trans­fer infor­ma­tion from one quan­tum to anoth­er with­out them touch­ing or being close to each oth­er, how can we be sat­is­fied with an inter­pre­ta­tion that some peo­ple will asso­ciate with vol­un­tary blind­ness ? Are we afraid ?

It is now one hun­dred years since real­i­ty is no longer that of New­ton, since some sci­en­tists tell us that our con­cep­tion of real­i­ty is out­dat­ed, that our con­vic­tions are in fact a virus that feeds tire­less­ly on the pover­ty of our senses.

It is true that the mak­ers of good news and com­mer­cial mys­ti­cism or ill-behaved have thrown them­selves on these dis­cov­er­ies with­out prov­ing any­thing. One can under­stand those who pre­fer the Copen­hagen axioms because no place is made in them for the char­la­tans who flood the book­shops. It is too easy to col­or the unknown with the cur­tains of our fears. We exist, we sit on chairs, we feed our­selves with the mat­ter, we touch our­selves because we are things. But this bor­der would be thin, even imag­i­nary. How long, how many cen­turies, how many mil­len­nia will the human species need to over­come a con­cep­tion of real­i­ty that is only two hun­dred years old ? We are not eter­nal in the form that we know. It is quite pos­si­ble that, if we sur­vive in a way to our body, we would not be, in any case, our­selves, would be only infor­ma­tion return­ing to the fold of the uni­ver­sal memory.

Does this real­ly make sense ?

Is it true that ancient man spoke to trees before the inven­tion of real­i­ty and that it would only take a lit­tle pas­sion and open­ness to be able to do so again ? Is it true that the uni­verse is too coher­ent to be the result of chance ? That it is the same every­where ? Isn’t there a mys­tery that should make us hum­ble and, above all make us stop the mas­sacre of our lives and our planet ?

Let’s for­get the church­es and their cer­tain­ties, but let’s keep our eyes open to dreams and imagination ?