It is not Buddha. It is Vedanta -end part of the Vedas - that define - consciousness -as Consciousness is infinite - prajnaanam brahma. the mind reflects the all-pervading consciousness and by reflecting it acts as though a local conscious entity -just like moon by reflecting sunlight appears as though a luminous entity in the sky. Any observation involves this activated mind. Hence the observer is the local mind + the reflected consciousness that makes the mind as though a conscious entity. Any objective knowledge involves mind interacting with the information provides by sense input -here measurement itself. Interference happens due to Hysenburg uncertainty at these small scales. Hene observation can affect the observed at such a small scale. For more info listen to my talks on youtube or I have written few books on it available on Amazon. I am a material scientist.