At long last, a unified theory combining gravity with the other fundamental forces—electromagnetism and the strong and weak nuclear forces—is within reach. Bringing gravity into the fold has been the ...

Operant conditioning, sometimes called instrumental conditioning or Skinnerian conditioning, is a method of learning that uses rewards and punishment to modify behavior. Through operant conditioning, ...

If we want to understand complex constructions, such as ourselves, assembly theory says we must account for the entire history of how such entities came to be. Life on other worlds — if it exists — ...

Fifty-eight years after it first appeared, string theory remains the most popular candidate for the “theory of everything,” the unified mathematical framework for all matter and forces in the universe ...