We know that when many particles are shot through the double slit they make an interference pattern. Also when a single particle passes through double slit it makes an interference pattern, ie one particle passing through two slits at once. But when we put a particle detector near the slits that beeps when it detects a particle, the particle doesn't make an interference pattern, which means the particle knows that it is being observed? Does a particle have a conscience of its own? If so then how come it can't observe other particles and collapse their wave-function? Thank you for you answer.