The new quantum mechanics was first presented in matrix form by Heisenberg in July 1925 (followed up by Max Born and Pascual Jordan in September) and then in wave equation form by Schrödinger in February 1926. Although Schrödinger quickly understood that from an abstract mathematical point view the two formulations were in some sense equivalent, they expressed fundamentally different physics and so Heisenberg and Schrödinger became fierce opponents in a fight eventually won by Heisenberg in the form of the probabilistic Bohr-Born-Heisenberg Copenhagen Interpretation of stdQM, even if (ironically) his matrix mechanics was superseded by Schrödinger’s wave mechanics.

But initially Heisenberg was seriously shaken by Schrödinger as told by Heisenberg in1968:

*In July 1926 Schrödinger was invited to Munich by Wilhelm Wien to report on his theory. The experimental physicists in Munich, headed by Wien, were enthusiastic about the possibility that now perhaps this whole “quantum mystery of atomic physics” might be dealt with, and one would be able to return to the classical concept of honest fields, such as one had learned from Maxwell’s electromagnetic theory. I listened to this lecture by Schrödinger and I was then really horrified by his interpretation, because I simply could not believe it. I objected in the discussion that with such an interpretation one would not even be able to explain Planck’s heat radiation law. But general opinion at that time was extremely hostile towards my objection. Wien answered me harshly in that he could understand that now I felt sad about the fact that the quantum jumping, the matrices and all that, had become superfluous; but it would be better, anyway, for me to leave the field to Schrödinger, who would certainly solve all the difficulties in the near future. This was not very encouraging; I did not have the slightest chance to get across my point of view in the discussion.*

Heisenberg eventually took the game by sacrificing the most fundamental principle of physics of causality in a turn away from rationality, which he rationalised as a necessary shift from exterior objective reality to interior subjective observer psychology:

*Not only is the Universe stranger than we think, it is stranger than we can think.**What we observe is not nature itself, but nature exposed to our method of questioning.**The reality we can put into words is never reality itself.**In classical physics, science started from the belief – or should one say, from the illusion? – that we could describe the world, or least parts of the world, without any reference to ourselves.*

Here is Heisenberg’s view of Schrödinger’s wave mechanics:

*The more I think about the physical portion of Schrödinger’s theory, the more repulsive I find it…. What Schrödinger writes about the visualizability of his theory “is probably not quite right”; in other words it’s crap.*

Here is Schrödinger’s view on the quantum jumps of Heisenberg’s matrix mechanics:

*I don’t like it, and I’m sorry I ever had anything to do with it.*(About the probability interpretation of quantum mechanics)*If all this damned quantum jumping were really here to stay, I should be sorry, I should be sorry I ever got involved with quantum theory.*