But where is this evidence that gravity affects time as well as clocks?

Observed reality is that gravity affects clocks. Any further interpretation of that fact is evidence you need to produce. Quit trying to shift the burden of proof for your idea onto me. :thumb:

I’m just trying to get a clearer idea of what this nebulous idea called “time” is to you. You say the onus is on me. I touched on this before, but I will elaborate a bit.

My first clarification that takes time from a vague concept is during the latter 1800s. It was then that Maxwell, starting with well-understood foundational ideas in physics, saw the connection tying together a hodge-podge of ideas in electricity and magnetism. He merged them beautifully into 4 simple calculus equations now known as Maxwell’s Equations. The problem was that these 4 equations did not dove-tail cleanly into Newton’s version of physics. For a few decades the rub between the two was largely ignored, and that worked well because seldom did anything about electricity or magnetism have to do with gravity.

Late in the 1800s a mathematician named Lorentz undertook what was largely an intellectual exercise trying to find a mathematical description of how Newton’s world would relate to Maxwell’s. He came up with what are famously called the Lorentz Transformations.

Now the second point. A few more years and a young man named Einstein looked at the Newton Maxwell issue from a different approach. Out came Special Relativity, and along with it the Lorentz Transformations showed up again. This time though, it was not an exercise in mathematical formalism like it had been for Lorentz, but an attempt to unify two descriptions of physics. And time – not clocks – but time itself, was required in Lorentz’s equations to be changeable.

Then the third approach – the empirical one. If time itself can be varied, then it should matter not at all what principle a clock operates on. In a situation where time is expected to be altered, every clock would be expected to agree in that alteration. And they do. Regularly. In places like particle accelerators, a million times a day time is seen to be stretched or compressed.

So, in summary, as a conclusion of a purely formal mathematical treatment, time was seen to vary. Then as a conclusion of an analysis from the needed physics, time was seen to vary. Then in the lab, time was measured as varying.

Now your answer is that it is the clocks that are being affected, not time itself. But time is – listen carefully now, measured by intervals between events. If gravity is changed, and the interval is seen to change, then it may be the clock has changed. Or not. One clock is a dripping seal bladder. One is a crystal electromagnetically resonating. One is how long it takes light to bounce between a couple mirrors a thousand times. One is how long a nuclear particle takes to decay. One is a pendulum. There is not commonality in how they work, and some could care less about variations in gravity. But they all measure the same intervals, and they agree with each other, whether in low or high gravity.

Now to you. Do you agree that time is the interval between events? If not, please tell me what you envision time as. It has to be something meaningful, that we can jointly subject to some sort of study, so we can see who is right about whether it is invariant or not.

In a high gravity environment, what (beyond you just saying so) are you going to do to show that the time has not been altered?