The question is whether intelligence of the sort that can understand and make use of science has evolved elsewhere. Intelligence has sprung up on our planet in response to competitive pressure. When the first humans clambered out of the African savannas, they confronted an environment in which the number of species had reached an all-time high, twice as many as when the dinosaurs held sway. The world was a brutally competitive place. Brain power, like keen eyesight or sensitive hearing, conferred an advantage in this heightened battle for survival.
Intelligence promotes adaptability.
It may be a common solution to the challenges of a tough, terrestrial environment populated by sophisticated competitors. If life on the other planets has similarly become diverse and competitive, it may also produce intelligent creatures. This argument for smart E.T.s is based on the concept of convergent evolution. In nature, a common set of environmental circumstances will result in animals whose designs are analogous. For example, in the viscous undersea environment, we find a plethora of torpedo-shaped animals, for the obvious reason that streamlining increases speed.