Who was the all-time greatest hitter?
A lot depends on how much weight you give to batting average versus power hitting. But it would be hard to consider someone for the title of the all-time greatest hitter if someone else had both a higher lifetime batting average and a higher lifetime slugging average. That narrows down the list considerably.
The highest lifetime batting average was Ty Cobb's .367. But Rogers Hornsby hit .358 and, being far more of a home-run hitter, Hornsby had a higher lifetime slugging average than Cobb. No one had both a higher lifetime batting average and a higher lifetime slugging average than Cobb or Hornsby. Both of them therefore belong on the short list of candidates.
Babe Ruth had by far the highest lifetime slugging average -- .690. Batting averages count how many hits there are in how many official times at bat. Slugging averages count how many total bases there are from these hits -- counting a single as one base and a home run as four, for example.
If you get two singles and a double every 10 times at bat, then your batting average is .300, and your four total bases mean that your slugging average is .400. If you get two singles and a home run, then your six bases give you a slugging average of .600.
Babe Ruth's lifetime slugging average of .690 means that he averaged nearly 7 total bases every 10 times at bat. That would mean something like a single, a double and a home run every 10 times at bat -- over a span of 22 years.
Some great sluggers, in their best seasons, have had slugging averages of .700 or more, usually once or twice in a lifetime. Only two players -- Babe Ruth and Barry Bonds -- ever had a slugging average over .800 in a season. That's equivalent to two singles, a double and a home run every 10 times at bat, all season long.
But if we are talking about the all-time greatest hitters, we usually mean over the course of a career, not just in a particular season when a batter was hot.
To put the Babe's .690 lifetime slugging average in perspective, even such great sluggers as Hank Aaron, Willie Mays, Joe DiMaggio and Hank Greenberg, in their greatest seasons, never had a slugging average as high as the .690 that Babe Ruth had for his whole career. So the Babe makes the short list.
Ted Williams is best known for batting .406. What is not nearly as well known is that he had a lifetime slugging average exceeded only by Babe Ruth's -- and Williams' lifetime batting average of .344 was two points higher than the Babe's. So no one had both a higher lifetime batting average and a higher lifetime slugging average than Ted Williams. He too makes the short list.
There is another important dimension to batting, the ability to come through in the clutch. This is not so easily quantifiable. However, there is one batter who stands out above all others when it comes to runs batted in -- Lou Gehrig.
Despite a career shortened by the disease that bears his name, Lou Gehrig still holds the record for the most seasons with more than 150 runs batted in -- seven seasons, one out of every two full seasons in his career. Babe Ruth is second with three seasons of 150 or more runs batted in. Gehrig had 184 RBIs in 1931.
Lou Gehrig also set the lifetime record for the most home runs with the bases loaded, a record recently tied by Alex Rodriguez. Babe Ruth, Hank Aaron and Barry Bonds, in their longer careers, hit over 200 more home runs than Gehrig, but none of the three hit as many homers with the bases loaded.
Lou Gehrig's lifetime slugging average is third on the all-time list, just one point behind Ted Williams'. Gehrig's lifetime batting average of .340 is 2 points lower than Babe Ruth's and 4 points lower than Ted Williams'. But, if clutch hitting counts, Gehrig also belongs on the short list of all-time great batters.
We can argue about how to weigh various aspects of hitting, in order to pick the one all-time greatest batter, but at least we can narrow down the list of possibilities to five.