Some days it's tough to be an optimist about the market - recently we've had more than our share of those days.

Whether it be gloomy news from the US on the housing meltdown or unemployment levels, concerns about a U.S. recession spreading globally, banks around the world announcing more mega write offs on subprime debt or reports of another Canadian manufacturer being hammered by the dollar, pessimism seems the order of the day.And we may indeed be facing some very tough times in the immediate period ahead. What about the mid to long term however?

If you go back in time, business and political leaders and economists have generally been overly pessimistic in their forecasts for the mid and long term growth of the overall economy. (This contrasts with comparatively rare occasions when they've been unduly optimistic, the tech bubble was one instance of over optimism.)

The reason that people tend to underestimate growth is quite simple: It's human nature to extrapolate from what we know. By definition, it's very hard to factor in things coming down the pipeline which haven't hit the radar screen.

One example: If you looked at media coverage of the computer business in the late 70's, the consensus was that computers would be a good business to be in going forward, but not nearly as good as they'd been through the 70's, when mini computers replaced mainframes in large and mid sized companies. Virtually no one saw the PC coming.

Similarly, if you looked at media coverage of the computer business in the late 80's, the general view was that computers would continue to be a good business to be in going forward, but not nearly as good as they'd been through the 80s, as the personal computer had saturated workplaces. Almost nobody saw the arrival of the internet and personal computers achieving dominance in the home.

If you accept that innovation fuels economic growth (and economic growth drives growth in market valuations), there are lots of reasons to be optimistic. We have more research taking place around the world than ever before (Sir John Templeton makes the case that there are more scientists working today than worked through all of human history until 1900) - and not only are there more resources allocated to research and innovation, but the rapid dissemination of knowledge via the internet makes them much more productive.

To this can be added lots of other good news at a macro level. The rapid growth in educational levels globally is a hugely positive development - nothing correlates more strongly with growth in an economy. Strong economic progress and political stability in historical dysfunctional South American countries like Argentina and Brazil is another positive. Still a third good news story is the unstoppable momentum towards opening up of traditionally closed markets (not just China and India but all of Eastern Europe and countries like Vietnam; we also have leadership in Germany and France that is moving to more market driven economies).

Finally, for those concerned about a long decline for the U.S. economy similar to that experienced by Japan in the 90's, no less an authority than Warren Buffett had reassuring words in last week's speech to the Toronto Board of Trade about the resiliency of the U.S. economy and his positive take on future prospects there.

Going forward, there will be clearly be losers as well as winners - not just among companies but among industries and countries. For those clients taking the long view, however, there is indeed lots of reason to be positive going forward.

I've written before about the advisor's job as an emotional anchor, preventing the lows from being too low and the highs too high. In many cases, your job right now is to temper current fears, helping clients stay positioned for the opportunities that history suggests lie before us. You may well disagree with some aspects of the argument I've made - in which case you should craft your own case for balanced optimism. Providing perspective on the longer term case for a positive outlook may be one of the most important things you do to serve clients in the period ahead.