Are there ghosts? I do not know. And it doesn't help to believe in what you do not know. I will say, however, that relying on science to find ghosts may be a completely wrong approach, because science can only measure what is measurable. If a ghost is not measurable by scientific instrumentation this doesn't mean that ghosts do not exist, but rather that science cannot detect them. Science is limited in what it can measure. This is a fact. So where does this leave us? If you see an apparition, clearly and without a doubt, then it seems to exist whether science can prove it or not. After all, science cannot prove how you feel, what your thoughts are, what a thought is, or even what consciousness is.