This seems to go against common sense. How can you have a physical body and be “just” a thought form?
First thing you need to realize is, thoughts are real and they have eternal existence, apart from anything “physical.” Go back to your idea of God, whatever it is and however well or poorly defined it is. In the “mind” of God, all of us are thought forms. We might be 50 or 500 or 500 million levels down from “god,” who created beings, who then created more beings, and so on. How did each being start? As a thought form.
But these thought forms develop their own personality and go about their own development, making decisions and choices and using their own “free will” to create whatever type of experience they wish. We are thought forms of our “Big Self” and we grow independently, making our own choices, etc.
Our basic reality is that of spirit, but when we participate in the low-frequency world of matter in order to play the Earth game, we agree along with everyone else playing the game that we all have solid bodies and objects are real and solid. Once we are out of this perspective, via “death” or an out-of-body experience, however, we realize that we can easily pass through these supposeldy solid objects and bodies.
So the bodies are as we know temporary, and the eternal existence is that of us independently developed “thought forms” whose basic reality is in spirit form, not physical. We’re all living “from the inside out,” creating the reality we know with our thoughts,beliefs and emotions.
And what is our most intimate creation? Why our bodies of course! We’re constantly creating it in whatever form it is, and using it as our base of operations, we create what we experience through the five senses while we are in the body. Most of us today don’t realize that we do, of course, but as people gradually come to realize that in the next century, physical life on earth is going to be a whole lot more enjoyable and exciting for millions of us!
Thoughts like these are summarized in my book, You’re Bigger Than Death … and life too, but they are very well explained in my two favorite Seth books by Jane Roberts, Seth Speaks and The Nature of Personal Reality.