"The theory of superstrings... described the world as a vast symphony of vibrations of infinitesimal strings in a 10-dimensional spade-time. The world would then be governed by a single superforce, melding all four currently known forces, and whose rule would extend over the entire universe. Are we about to reach the goal? ...I am not convinced. It is, for the time being... to be verified experimentally, since it would require phenomenal energies. ...protons have displayed a longevity surpassing initial predictions. ...the unification of everything is predicted at energies that defy human imagination... the theory is shrouded in such a thick mathematical veil that it no longer has any connection with reality. ...as long as physics is not rooted in reality, it is no more than metaphysics."
January 1, 1970
https://en.wikiquote.org/wiki/Theory_of_everything