# The danger of biting at ankles

You tend to get kicked in the teeth a lot:

Ok, so we go the whole day and no-one points out that free fall most certainly is acceleration. 9.8 m/s/s, to be exact.

The statement was not “freefall is not acceleration”, but that “acceleration is not freefall”. Does an orbital rocket blasting off accelerate? Does an automobile? And are either of these machines in freefall while they are accelerating as per their normal operation?

Some commenters appear to have an amount of trouble understanding the concept of sets and subsets. The subset is not, and cannot be, the set of which it is merely a part. (Cue Markku bringing up the null set.) I tend to doubt anyone would have felt the need to attempt offering a correction had I stated, for some inexplicable reason, “Numbers are not nine”. I desperately hope, anyhow, that even the most cluelessly contrarian anklebiter would have been able to resist the urge to reactively insist that “Nine is a number!”

Yes, it most certainly is. But three is a number and it is not nine. Ten is also not nine. There are, in fact, a vast collection of numbers that do not happen to be nine, just as there are many rates of change of velocity over time that do not involve the motion of a body where gravity is the only force acting upon it. The two terms overlap, but they are not interchangeable.

So, a helpful word of advice to the pedantically inclined. If you make a habit of actively seeking to criticize others or just have a tendency to react to assertions in an instinctively contrarian manner, I suggest learning to first ask questions rather than immediately attempting to offer corrections even when you are reasonably sure that you have understood what the other person said. Always get confirmation first. Because when you are dealing with anyone who is reasonably intelligent or even just precise in their thinking, there is a very good chance that your posturing – and let’s face it, that’s what it is – is going to cause you to make an ass of yourself by trying to correct something that is not, in fact, incorrect.

I understand that my towering intellectual arrogance is infuriating to some readers. Even those who often agree with me are sometimes sorely tempted to attempt to “bring me down” when they perceive an opportunity. But not every red flag waved in your face merits a blind and heedless charge. If you’ve read this blog for any time at all, you should be aware that there are few things in which I find more personal amusement than publicly skewering a superficial and reactively contrarian would-be critic.