lfPatriotGames - So you're basically saying sport is physical? How much physical? 100, 70, 60, or even just 1% physical?
All physical sports are mental to a degree obviously. But what about precision sports that actually have little physical involvement? Imagine marksmanship (i.e., shooting a target at 1200 yards). Sure, you have to hold the gun and pull the trigger, but the true skill is the incredible velocity calculations and understanding the effects of the environment on your projectile.
But because elite marksmen spend massive amounts on the gun in their "game of choice," plus regulating their breath and shot - marksmanship is a sport? Because honestly, it's 99% mind and 1% physical. Are darts a sport? Professional marbles? Washers? Quilting competitions?
„Which means any mental activity, like thinking about how to grow rhubarb is a sport.“
No. It is no exercise. Likewise not any walk of two meters is a sport.
„it didn't make sense to label every single human activity (mental or physical) a sport.“
I agree. I wanted to have short premises. You almost never include all conditions. So, if you will, premise (1) is
„(1a) Sport is exercise (fitness) of a part of the body in a competitive manner.“
When you assure „Water boils at 100 degree Celsius“ you also don't mention all other necessary requirements.
You don't get to cherrypick. You do have to be true to the general principles. Thinking about how to grow rhubarb is a sport because it's mental exercise and all mental exercise is sport.
That's your opinion. I disagree.