"Is there anybody out there?" is a question currently popularised by the media fascination with UFOs and Alien conspiracy theorists, but what is often overlooked is the introspective, philosophic slant to this question, where "out there" is not outer space, but outside the inner space of the mind. To put it another way: "Is there any mind but my own?"
A sceptical philosopher could argue that we cannot trust our senses, as there is no way to verify what we see, hear, smell, and feel. Who hasn't mistaken an innocent silhouette for something more sinister? Or awoken to discover that what you thought was real was in fact a dream? If it is that the things and people around us don't exist then they can't have minds, and we are alone. But say for a moment that we can trust our senses (for even if we cannot trust our senses there is nothing we can do about it, so why not continue living our lives as if we can?) and that those around us are not figments of our imaginations, then their presence and behaviour must confirm the existence of their minds. Not so, consider computers, I have seen a program that takes typed sentences and reorders them into questions, for a while it quite convincingly mimics a psychiatrist. Computers are just machines, and no one I know would argue that they, or this program has a mind. It is quite possible (although quite hideous) that - as I mentioned in my last essay - everything around one is also just a machine, a complex set of mechanisms that mimics a conscious mind, but even if other people are biologically the same as us what is to say the have minds? Conversely we may be surrounded by many, many, more minds than we ever considered, who is to say a cat does not consider the meaning of life as it dozes by the fire, that a cow does not ponder the meaning of goodness, or even the bee as it buzzes from flower to flower, may be thinking about the mind / body problem, and a tree may for all we know spend the day wondering at the might of the sun.
When considering this question one must also consider the problems of defining the mind and conciseness, and somehow decide what or who is anybody. Until these terms can be defined we can never know if there is anybody out there, but I would, for the sake of your sanity, assume that there is.