If we drop a stone into a calm body of water, it sends out circular waves. As the waves move outward, the clock is ticking and we say the dropped stone caused the waves, which are an irreversible process in time. But we would also say the waves are moving in space, so why isn’t it an irreversible process in space? It is, we just don’t ordinarily speak that way.
What is the difference between the “now” and the “here”? The now is the present, which seems to move with us in time. But the here moves with us in space, like a webcam that follows us everywhere.
Is the past where we were or what we were? It’s both. Is the future where we will be or what we will be? Again, it’s both. Events in times past can cause events in the present time, and events in places past can cause events in the present place. There is an exact parallel.
Causality is transmitted through time and space. We’ve heard this in relativity theory but we don’t need relativity to realize it’s true. The world line of an object in space and time is subject to causality in space and time.
But just as space has three dimensions (directions), so does time. So causality has what — six dimensions? No, causality has three dimensions because they are the same three dimensions. This is no different from saying that force has three dimensions, which are the same three dimensions as space. Dimensions are a property that applies to vector quantities.
We’re so used to thinking that dimensions are spatial but they are just as much temporal — and dynamical (having to do with force and torque) and a property of every other vector quantity in physics. Dimensions are an abstraction that applies to many physical quantities.