Thanks for the comments of the panelists and commentators here. I would like to add my views here.

Another difference between investing and speculation is the definition of risk management. Investors emphasize on the movement of intrinsic value, whereas speculators care about pricing fluctuation (Beta/Sharpe/etc).

The panelists' comments are highly sophisticated, which is not understandable for the laymen. As a investment professional too, I would still prefer to look into investing-vs-speculation a simple context. Investing = buying a cow that milks every day and expect the value of cow to increase in the future; speculation = buying a cow and expect to sell next day/week/month/year by guessing how other buyers think.

As pointed out by many readers, speculation is all about guessing work. Speculators predict -- with and without reasonable basis -- the future growth, future market valuation, future economic environment, future human behavior, future bla bla bla. It is about predicting the future, in which the probability of error is at best 60-40 (normally 50-50). Therefore, speculation is generally risky, hence a speculating-CIO normally needs a risk management department sitting beside his/her office.

Investors, on the other hand, don't predict. Investors look into what an asset can produce and conservatively estimate the intrinsic value over the productions. At times, investors do predict future growth but with reasonable assumptions (conservative is the key). Any "investor" who predict growth without basis or with unreasonable basis should move to the speculation camp.