A goblet squat is a movement that takes place in the frontal plane. If you are stood in front of a person doing a squat, you won’t detect much movement. View them from the side, however, and you’ll see the hips come back, the knees drive forward and the angle of the torso change as they descend, and all this will reverse on the ascent.
A cossack squat is a movement that takes place in the lateral plane. Stood facing them you will see much movement—the step to one side, the movement of the torso towards the outstretched leg and back. Here’s what this actually looks like:
What about a roundhouse kick? It is a movement that is multi-planar. There’s action on both the frontal and lateral plane. So would we be right in assuming that someone who is proficient at a goblet squat and a cossack squat would be proficient at a roundhouse kick? Of course not. Aside from the skill and practice required to master a kick, there’s the matter of the transitions between the planes.
I’ll simplify. Search up some “yoga flows”. You’ll find multi-minute sequences that chain together different yoga poses. Why are a lot of these particularly difficult to accomplish? It’s not the positions themselves—someone with good hip flexibility can hold the “Warrior Pose” and the “Pigeon Pose”. It’s the transitions. See, it’s one thing to access different planes of movement. It’s another to traverse the illegible space between them.
Pop this into a hierarchy. The lowest level of movement capacity is signalled by proficiency in a single plane. The medium level of movement capacity is signalled by proficiency in multiple planes. But the highest level of movement capacity is signalled by access to all planes of movement and the ability, not only to shift effortlessly between them, but to exist in the dimensions between them. Watch videos of people like Ido Portal moving and you’ll see movements and positions which would severely stress the bodies of most of us.
Enough about movement. This hierarchy of single-multi-transitional applies to intellectual activity too. From bottom to top: a person who has a deep understanding of one domain of knowledge, a person who has a deep understanding of multiple domains, and a person who has a deep understanding of multiple domains and can hang in the bizarre space between them.
The latter is a basic description of the people whose work I find most interesting and useful, and it is also a description of the sort of thinking I am striving for.