Edaw asked:

If we think of a ball bouncing, then we stop thinking about it, and then we think again of the ball
bouncing, has the ball being bouncing the whole time?

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Hopefully you mean "has the ball we were thinking about" been bouncing... Well I'm really not sure
why I'm answering this... look. Suppose you think of (i.e., visualize, rather than merely, for example,
read the first sentence above) a ball bouncing. Ok. Then you stop. For how long? A millisecond, a
minute, an hour, a week, 10 years? What does "stop" mean? Completely switch consciousness to
other experiences? The answer is: if you stop (in that sense) for a veryshort interval, then the neural
processes realizing the experience you're having (visualizing the ball) may not have had time to
completely stop, to dissipate, to realize something else. So if you switch back really fast,probably on
the order of at most about 1/2 second, you might be able to claim that the "ball", i.e., the visualization
of the ball, has in some sense continued. Otherwise, no.

Steven Ravett Brown

Suppose you ask me to think of a ball that has been bouncing for a while. It would be absurd to think
that in order to do this, I have to picture the ball as it starts to bounce, then return to my mental image
of the bouncing ball some time later.

When we consider the nature of thinking, we are tempted to think of it as simply picturing, using
imaginary coloured pencils or paints on my mental drawing paper. But that can't be right. I can make
the ball red by putting red in the picture, but I can't make the ball heavy or light by putting 'heavy' or
'light' in the picture. (As an exercise, think how you one actually might try to do this: picture a man,
grimacing with effort as he holds the ball. What makes this picture, a picture of a heavy ball rather
than a picture of a very weak man?)

Similarly, my mental picture of a ball that has been bouncing a long time might have paint flaking off,
the surface of the ball badly scuffed, and so on. But these marks alone do not suffice to mean 'a ball
that has been bouncing for a long time'. Obviously, there are other ways in which the ball could have
been marked in this way.

What makes my image of the ball what it is, what gives the ball I am thinking about its qualities
depends on the verbal descriptionI would be prepared to give.

But here's a reason for second thoughts. While I was typing the last sentence, I started a tune in my
head,

"A very old friend

came by today

'cause he was telling everyone in town

of the love that he just found..."

As I concentrate on continuing to write, did Elvis Presley stop singing or did the tune merely fade into
the background? I stop writing and notice that I have now reached the second verse,

"He talked and talked

and I heard him say

that she had the longest, blackest hair

prettiest green eyes anywhere..."

This looks like an empirical question. How would one devise an experiment to decide, one way or the
other? Come to think of it, why can't I start a mental ball bouncing to mark the passing seconds, '1
bounce, 2 bounce, 3 bounce...' and return to discover that it took just 12 seconds to finish this
sentence? Doesn't that show that I can make my mental ball bounce when I'm not attending to it?

What does that prove? Nothing. All it shows is that to thinkabout a ball bouncing is not the same as
bouncing a mental ball. One can think about a ball bouncing without conjuring up any image of a ball,
just as one can run a mental tape of a bouncing ball — or Elvis — without thinking about a
ball or about Elvis.

Geoffrey Klempner