Note that, while I was being sarcastic above, I was also making a more subtle point about methodology. Moving a carefully balanced pencil by blowing it involves fairly simple physical laws, and classical mechanics. However, moving it with only one's mind seems to require unknown aspects of physics why defy current scientific understanding. Of course, this is assuming that if telekinesis is real, it must at some level be a manifestation of physical law and not something truly magical or supernatural. So, if a real force can be applied to objects by one's mind, ultimately there must be a physical means by which this can occur. What might this be, and how might it work?
Occam's razor suggests that we ought to prefer the simpler explanation, the one which makes the fewest extraneous assumptions. In this case, that would imply that we should prefer the blowing hypothesis over the possibility of telekinesis. Further, the blowing hypothesis is easily falsifiable; put the balanced pencil in a vacuum and see if you can still move it, or just use a simple barrier to stop air movement. There is still much more to say about scientific methodology and why it ought to be preferred... but this is a start.