A business needs time to do its job. A ship might take two years to build, and thus a shipbuilder cannot be evaluated on quarterly orders, or daily prices of oil. It is evaluated over multiple business cycles to see how it performed operationally, managed its cash flow, managed its customers, etc.. The shipbuilder could be listed and its stock could fluctuate on every news item on world trade, oil price, new orders, lack of new orders, etc.. The business has to be managed differently to the news flow; it has its own internal clock. This clock will be different for a software company (most software patents become useless well before they expire) and an iron ore miner (mine lives may run in decades).
The fund invests in businesses, using stock as a means to get exposure, not as a call on the stock itself. The returns of the fund come from the health and growth of the businesses. Investing in the stock of a good business at a cheap (low) multiple gives a possibility of a double boost: the underlying growth over time, and a one-time boost from the (upward) re-rating to a fairer multiple.
Different funds can be run with different styles and philosophies and time horizons. I think well when I think deep, slow and deliberate. My chess rating for a slow game is 25% better than for a Blitz game. We set the internal clock for the fund at three years; it is about half a business cycle.