Something <i>fundamental</i>.<p>There&#x27;s a qualitative difference between fundamental and incremental innovation.<p>An example of a fundamental innovation would be radio. Before radio there was... no radio. Nobody could communicate across vast distances invisibly and without sound. After radio, they could. It&#x27;s an absolute, sharp discontinuity.<p>An example of an incremental one would be multi-core processors, self-driving cars, or reusable rockets that land themselves. These are awesome don&#x27;t get me wrong but they&#x27;re refinements of things we already have. We already had cars, CPUs, and rockets, and now we have better ones.<p>The line is not <i>perfectly</i> sharp. Were ICs fundamental or just a refinement of transistors? (I&#x27;d argue that the photographic down-projection of circuitry in that way was fundamental.) But I think it&#x27;s fairly clear to me that nothing of even the magnitude of the IC has come about since 1970. Certainly there hasn&#x27;t been anything of the magnitude of radio, electromagnetism, powered flight, or rocketry in a long time. The last was probably understanding DNA and the DNS-&gt;RNA-&gt;protein synthesis pathway.<p>At this point I&#x27;m fairly convinced that this doesn&#x27;t work, but if it <i>had</i> worked it would have qualified:<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;RF_resonant_cavity_thruster" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;RF_resonant_cavity_thruster</a><p>&quot;Cold&quot; fusion, had it actually worked, would also have qualified. Something like <i>that</i> would convince me we have not entered a new dark age.<p>A possibility I didn&#x27;t mention in my OP is that we&#x27;ve hit the limits of human cognition. I find it hard to believe that we understand &quot;all of science,&quot; but maybe we are close to understanding all that the brain of homo sapiens can process.