> > do you deny that the brain has to set in motion the muscular activities in advance?
> What do you mean by "in advance"? What does that mean? That's an empty phrase. In advance to what? When it moves the arm to catch the ball it moves to what is there right now.
It mean it according to the standard meaning of that phrase. It's not empty.
Here's an example to illustrate my point. It's simplified to make the point easier to understand.
The ball is moving.
At time T, the ball is at position X.
At time T the brain has received the visual information about the ball at X. It then processes this information. The amount of time this processing takes is A1.
It is now time T+A1. The ball is has moved on to position X2.
At time T+A1 the brain sends signals S to the muscles. This takes A2 amount of time to reach the muscles.
It is now time T+A1+A2. The ball is now in position X3.
The muscles do their contractions for reaching out and grabbing. This takes A3 amount of time to happen.
It is now time T+A1+A2+A3. The ball is now in position X4.
The brain started this process when the ball was at position X, and had to determine the signals S to send to the muscles based on details of the ball being at position X. But when those signals actually play out the ball is at position X4.
.
What I'm talking about is extremely elementary - it is simply the fact that perceptual+cognitive processing, plus nerve signals, plus the actions of muscles all take time! What you and the others are arguing would essentially require the absurd notion that it all happens instantaneously.
[EDIT: fixed some wording]
> What do you mean by "in advance"? What does that mean? That's an empty phrase. In advance to what? When it moves the arm to catch the ball it moves to what is there right now.
It mean it according to the standard meaning of that phrase. It's not empty.
Here's an example to illustrate my point. It's simplified to make the point easier to understand.
The ball is moving.
At time T, the ball is at position X.
At time T the brain has received the visual information about the ball at X. It then processes this information. The amount of time this processing takes is A1.
It is now time T+A1. The ball is has moved on to position X2.
At time T+A1 the brain sends signals S to the muscles. This takes A2 amount of time to reach the muscles.
It is now time T+A1+A2. The ball is now in position X3.
The muscles do their contractions for reaching out and grabbing. This takes A3 amount of time to happen.
It is now time T+A1+A2+A3. The ball is now in position X4.
The brain started this process when the ball was at position X, and had to determine the signals S to send to the muscles based on details of the ball being at position X. But when those signals actually play out the ball is at position X4.
.
What I'm talking about is extremely elementary - it is simply the fact that perceptual+cognitive processing, plus nerve signals, plus the actions of muscles all take time! What you and the others are arguing would essentially require the absurd notion that it all happens instantaneously.
[EDIT: fixed some wording]