A colleague of mine told me once about how a neighbor of his, just before summer break, 
said to him, ``Well, now that it's summer I guess you can relax and stop worrying about all that math.''  
The neighbor had thought that doing mathematical research was just a job, a chore that one 
gets paid money to perform.  I'm not sure whether my colleague attempted to explain that doing 
research is fun and meaningful work that gives his life a sense of purpose, and that he still can't 
believe he actually gets paid to do it; but even if he did, such an explanation probably wouldn't 
parse if the neighbor, like most people, never had the chance to experience the thrill of thinking 
creatively and discovering new truths. 

I myself often encounter some distant relative of what my colleague experienced when I introduce 
myself as a professor, and then get the question, ``Oh!, what do you teach?'',  the assumption being 
that professors are primarily ``teachers''.  I rarely ever have someone ask, ``Oh!, what is your field of 
study?'' or ``Oh!, what do you research?''  Teaching is, of course, very important, and I do take it very 
seriously; but I consider myself a researcher first and a teacher second.  

From what I have hinted at above, I hope you can see that material wealth is not the main motivator 
of scientists.  The promise of personal fortune does sometimes figure into where an academic 
scientist decides to work (at least to those scientists who actually have many options as to where 
to work), mainly to buy a house or to make sure family members can be well cared for; but a well-paid 
scientist at an institution without access to good colleagues working in a similar research area as 
oneself, without access to talented graduate students one can train, without the capability of 
making good hires in ones area (including postdocs), without adequate funding for ones experiments, 
is a miserable scientist.  

There is a secondary role that pay scale plays to some scientists beyond necessity and comfort, and that 
is that it sometimes is seen as a measure of ones worth -- quality of research, teaching, grants, etc.  
Arguments might arise when one colleague gets paid slightly more than another, when the one that is 
paid less thinks their work is just as good or better than the one paid more.  If every scientist were paid 
exactly the same, and one handed out ``gold stars'' when scientists did good work, I would bet there 
would be exactly the same grumblings over who had more gold stars as there are over who gets paid 
more.

The last thing I want to discuss is why scientists do science; that is, what drives them and what do they 
find enjoyable about their jobs?  For most scientists there is no one single thing that motivates them, but 
there is, rather, a combination of motivators, some of which are:

* The first and primary motivator is basic curiosity:  ``what would the human body look like under a 
microscope?'';  ``What are those points of light up there in the sky?'';  ``Is matter made of irreducible 
elements (i.e. atoms and fundamental particles), or is it infinitely divisible?''  There are some people 
who upon thinking about such questions try to discover their answers, and then there are those who 
simply don't care.  Scientists belong to this first group of curious minds. 

* Another motivator, which I see as distinct from curiosity, is ``love of the mysterious'' (as Einstein put it).  
It's one thing to be curious as to why gravitational force is inversely proportional to the square of the 
distance between objects, and it is quite another to be awed by this mathematical perfection evident in 
nature.  The latter feeling of awe and wonder, and sometimes ``strangeness'', as when one sees a magic 
trick or looks upon a surrealist painting, is what I mean by love of the mysterious.

* The simple ``pleasure of figuring things out,'' as Richard Feynman put it, is another motivator of 
scientists.  It is the same pleasure that one gets from working a puzzle, only that when it comes to 
science the puzzle is not a game -- there are consequences to when one ``figures things out''.

* Another is the trill of discovery and the electric jolt of emotion from having a ``Eureka!'' moment.  
Imagine what the first person to discover that the human body is made of cells likely felt: ``Good god!  
What... is... this?!  Is this what I am really made of?!  This will change everything!!!''  Or imagine the thrill 
from when in the early 80's experimentalists discovered the first high-temperature superconductors.  While 
most discoveries in science are not as grand as the two examples I just mentioned, there is still some of 
that same excitement to be felt ever so often in ones career; and once it has been experienced, the desire 
to feel it again is a powerful motivator to scientists.

* In some of the sciences, particularly medical science, there is the opportunity to save lives and to fight 
diseases.  This surely is a great motivator to those in such fields.

* Having ones discoveries and productions recognized by ones peers in peer-reviewed publications is 
another motivator.  One way of looking at this is that it is an example of ``ego gratification'', but a more 
accurate and more charitable view is that it figures into ones sense of purpose:  the fact that the larger 
community of scientists has endorsed ones work and uses and cites it means that one matters -- ``I matter 
to the scientists in my field of study and to the progress of the human race in general.''

* Lastly, there's no denying it, ambition is also a motivator (or rather, what drives some scientists).  
Pushing back the shadows at the frontiers of human knowledge is often a tremendous challenge, and there is 
a satisfaction at being able to say to oneself, ``I did that.  No human before me had noticed that or 
understood that.  With this discovery I leave my mark upon the world.''  However, some scientists get 
carried away with ambition, especially at the very best schools where in just about every department there 
are a few researchers consumed by it.  An example quote from a famous and highly revered scientist at one 
of the best research schools in the world: ``I'm as proud of my work as I am my children.  Think of it... 
do we remember Shakespeare's kids or do we remember Shakespeare's plays?''