Ordinarily pleasure and pain are regarded as different from sensations.
Personally, people know themselves very poorly.
My table is now brightly, now dimly lighted. Its temperature varies. It may receive an ink stain. One of its legs may be broken. It may be repaired, polished, and replaced part by part. But, for me, it remains the table at which I daily write.
The fact is, every thinker, every philosopher, the moment he is forced to abandon his one-sided intellectual occupation by practical necessity, immediately returns to the general point of view of mankind.
Man is pre-eminently endowed with the power of voluntarily and consciously determining his own point of view.
(This picture is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. - Original uploader was Bletchley at en.wikipedia)