What is string theory?
string theory
String theory is a theoretical framework in particle physics that models subatomic particles as tiny, one-dimensional ‘stringlike’ entities, seeking to reconcile quantum mechanics with general relativity. As of 2026, it remains unconfirmed, with key predictions like supersymmetry not yet observed.
How it developed
- Apr 2026 - Brian Greene said string theory’s hope rested on finding supersymmetry at the Large Hadron Collider, but those particles were not found.
- Apr 2026 - Brian Greene noted that string theory requires 10 dimensions, derived from the condition that the dimension minus 10 must equal zero.
- Apr 2026 - Brian Greene suggested the term “string hypothesis” because the theory has not made a testable prediction.
- May 2026 - Don Lincoln stated he does not believe in superstrings, calling it a fascinating idea.
- May 2026 - Michio Kaku described string theory as implying no initial bang, but a collapse and rebound.
- May 2026 - Don Lincoln predicted that 30 years from now, progress will be minimal.
In the evidence
Every line below is attributed to a named speaker.
Supersymmetric particles predicted by string theory were expected at the Large Hadron Collider but were not found.
“The big hope and the reason we believe that string theory might be 5 years away was we expected super symmetry which is the super in super string theory we thought it would be found those particles would be found at the large hydron collider and they were not found.”Brian Greene · 7 Apr 2026
Don Lincoln dismisses string theory despite its prominence as a Theory of Everything candidate.
“Super strings is a fascinating idea. I don't believe it.”Don Lincoln · 29 May 2026
Brian Greene argues string theory should be called 'the string hypothesis' because it has produced no testable predictions and does not yet meet the bar of a scientific theory.
“Maybe call it the string hypothesis.”Brian Greene · 7 Apr 2026
Mathematical consistency forces string theory to require exactly 10 dimensions: d minus 10 equals zero, so d equals 10.
“D minus 10 must be zero. Therefore, d must equal 10.”Brian Greene · 7 Apr 2026
Brian Greene on string theory lacking testable predictions.
“It has not made a prediction allowing us to determine whether it's correct.”Brian Greene · 7 Apr 2026
Carroll argues Peter Thiel explicitly targeted string theory as a wedge strategy to delegitimize academia broadly, using its prestige as a lever against universities.
“If you can undermine the idea in the eyes of the general public that people doing string theory, supposedly the smartest people we have and the best physicists, are somehow illegitimate, are somehow, you know, captured by institutional blah, then you've gone a long way towards undermining universities as a whole.”Sean Carroll · 13 Jul 2026
In string theory, the Big Bang was not an explosion from nothing but rather the universe collapsing to a very small size and then re-expanding, eliminating a true singularity.
“String theory, there was no bang. That is it did collapse. If you go backwards in time, it did collapse with a very small thing and then came out again.”Michio Kaku · 21 May 2026
String theory will make little additional progress in the next 30 years, per Don Lincoln.
“30 years from now we'll be not much farther along than we are now.”Don Lincoln · 29 May 2026