If you look for someone to confirm your angle on investing, the pros can help. If you look for someone to question your angle on investing, the pros can help as well. Welcome to the list of contradictory expert advice. Feel free to add to the list in the comment section.
(1) The classic: luck or skill?
The successful funds in any given year are mostly lucky; they have a good roll of the dice.
I want to present to you a group of investors who have, year in and year out, beaten the Standard & Poor's 500 stock index. The hypothesis that they do this by pure chance is at least worth examining.
(2) Diversification and Diworsification
Diversify. In stocks and bonds, as in much else, there is safety in numbers.
Sir John M. Templeton
Diversification is for idiots.
(3) Swimming with sharks or closet trackers?
Let me just say flat-out, you can't compete with these [superinvestors]. They are better than you and me.
Don't overestimate the skill and wisdom of professionals.
(4) P/E ratio rationale
We would suggest that about 20 times average earnings is as high a price as can be paid in an investment purchase of a common stock.
Benjamin Graham, David L. Dodd
[…] the P/E, no matter its level, by itself tells you nothing about market risk or return.
Kenneth L. Fisher
(5) Futility of forecasts
This idea that in order to make a decision you need to focus on the consequences (which you can know) rather than the probability (which you can't know) is the central idea of uncertainty.
Nassim N. Taleb
A [...] way is to beat competitors by forecasting more accurately--for example, correctly deciding that there is a 68% chance of something happening when others foresee only a 60% chance. This is the approach of the best poker players.
Philip E. Tetlock
(6) Investment themes
…my proceeds from PayPal after tax were about $180 million. $100 million of that went into SpaceX, $70 into Tesla, and $10 into SolarCity. I literally had to borrow money for rent. That was a close call.
Does anyone really need a billion dollar rocket?
Does anyone need a $60,000 car?