What does "structural tension" mean in this paragraph?

Question

I'm reading a book called "A New Earth: Awakening to Your Life" by Eckhart Tolle. In this book the author writes that enthusiasm will help us to be creative and that is what the new world needs. In the chapter about enthusiasm there is a paragraph as follows:

Enthusiasm mans there is deep enjoyment in what you do plus the added element of a goal or a vision that you work toward. When you add a goal to the enjoyment of what you do, the energy­field or vibrational frequency changes. A certain degree of what we might call structural tension is now added to enjoyment, and so it turns into enthusiasm. At the height of creative activity fueled by enthusiasm, there will be enormous intensity and energy behind what you do. You will feel like an arrow hat is moving toward the target – and enjoying the journey. To an onlooker, it may appear that you are under stress, but the intensity of enthusiasm has nothing to do with stress. When you want to arrive at your goal more than you want to be doing what you are doing, you become stressed. The balance between enjoyment and structural tension is lost, and the latter has won. When there is stress, it is usually a sign that the ego has returned , and you are cutting yourself off form the creative power of the universe.

Can you help me to understand "structural tension" in this paragraph? Thank you!

Answer 1

The author is creating a metaphor by comparing the relationship of enjoyment and a goal in creating enthusiasm to the mechanical idea of physical structural tension.

Structural tension is the concept that a structure under tension is stronger than it would be otherwise. A good example of this is tempered glass, which is actually pulling in on itself - it is stronger than regular glass but when it does fail it fails catastrophically (an explosive shattering instead of a spiderweb crack).