You see, life is filled with suggestions, I really don't think that you have a single thought of your own. Everything your mind can think of is based on an existing suggestion, from the experience of your history to the anticipation of your future. What you think you created by yourself in your mind, is actually inputted by many assumptions (necessity, pain, joy, hope, experience, anticipation, the list is just too long). The idea I'm trying to make is that we really don't have "an idea of our own" as we think we do. Everything is a combination of something, particles that come together to form our strong resolve might be from the seeming uninfluencal daily mundane activities that CAN'T mean much as a single force. You can trace this thought to every single idea that life holds, in that, the only thing that exists on its own is "the entity of nothing". Yea, nothing is an entity, it exists as an independent force.
So, when you set out to engage any thought or idea you "think" you have, make sure you take time to edit it, it might just be a suggestion from an irrelevant source.