All the time we have people declaring 'Ghost Forces'. This is somewhat a declaration that magic exists. I first ran into this with earthquakes, in that there were lots of ghost forces that supposedly 'caused' earthquakes. There was Earthquake Weather, clouds, and earth tide forces. Now we have 'carbon dioxide', 'chemicals attacking ozone', and 'sunspots making us warm or cold' etc.
In all these cases, people will cite correlations and have a long, persuasive argument. I am reminded of 'Chariots of the Gods' which was a powerful argument in favour of aliens influencing civilization. Any person can make a convincing argument of anything by cherry-picking facts and observations, and leaving out the messy things that disprove it.
A recent case is the proponent of a new force that can levitate things, just like Harry Potter. You can't just laugh at it and call it crazy, that's how the warmies work for their religion. Instead, you would have a hypothesis -- "There exists another force that is equally balanced by normal forces, so that it remains hidden.' Now, we can set experiments to test this hypothesis. The implication goes on that Newton's formula for gravity has another cubic term. We can attempt to measure all this, and the proponent would merely say that it is too small to be measured, just like warmies invoke extra effects for carbon warming. But there is another test of 'significance'. If this force or effect is buried under noise, and cannot be measured, then, for physics, it does not exist.
Now, we get back to ghosts. If they do not exert any measurable force on the world, they do not exist, despite all those people who see them. The Sun can vary it's output, by 0.1% It cannot be measured as an effect on the Earth because random noise is 100 times greater. The effect does not exist, and the same is with orbital variations. You need something more than 10% of other effects to be significant.
We can also have fun with a selected survey and say '99 percent of those who make their money from ghosts say that ghosts exist.' Now that's Scientific Proof!