What does it mean that feedback loops are circular relationships?

When A affects B and B affects A you have a system that can amplify or stabilize itself.

Example: Your body temperature rises above 37 degrees Celsius. Thermoreceptors in your skin and hypothalamus detect the deviation. The hypothalamus triggers sweat production and vasodilation — blood vessels near the skin dilate to release heat. Temperature drops. The thermoreceptors detect the return toward baseline and reduce the cooling response. This is a balancing feedback loop: a circular relationship where the output (cooling) counteracts the input (rising temperature). Walter Cannon coined the term homeostasis in 1926 to describe exactly this kind of self-correcting circularity. Your body runs thousands of these loops simultaneously — regulating blood sugar, blood pressure, pH levels, hydration — each one a circular relationship that keeps a variable within a survivable range. You are, at the most fundamental biological level, a collection of feedback loops.

Try this: Map one feedback loop operating in your life right now. Pick something concrete: your energy level, your spending habits, your productivity rhythm, your relationship with a colleague. Draw a circle with at least three nodes showing how A affects B, B affects C, and C affects A. Label each arrow with a '+' (same direction change) or '-' (opposite direction change). Then answer: is this loop reinforcing or balancing? Is it working for you or against you? If reinforcing, what is it amplifying — and do you want more of that? If balancing, what is it stabilizing around — and is that the right set point?