quantum physics tells us that nothing that is observed is unaffected by the observer
An especially unusual version of the observer effect occurs in quantum mechanics, as best demonstrated by the double-slit experiment. Physicists have found that even passive observation of quantum phenomena (by changing the test apparatus and passively 'ruling out' all but one possibility), can actually change the measured result. A particularly famous example is the 1998 Weizmann experiment. The ``observer'' in this experiment -- a sophisticated electronic detector -- wasn't human. And yet, possibly because the word ``observer'' implies a person, such findings have led to a popular belief that a conscious mind can directly affect reality. The need for the ``observer'' to be conscious has been rejected by mainstream science as a misconception rooted in a poor understanding of the quantum wave function ψ and the quantum measurement process.
Observer effect (physics)