The Four Faces of Luck

Luck is probability taken personally. Chip Denman.

The words luck and lucky are used in several ways, and I find it most useful to distinguish four usages. In everyday language, luck means "good luck", while in our general discussion, "luck" will refer to either good luck or bad luck; in practice this shouldn't cause any confusion.

I will try to frame the topic by explainng the four usages, and say a little about academic literature. Incidently, the current Wikipedia article on "Luck" is pretty bad -- someone please edit!

Four usages of Luck

1. Luck as superstition

This is typified by the belief that future good or bad luck can be influenced by such things as: actions that one might do deliberately (blowing out all the candles of a birthday cake) or accidently (breaking a mirror) or that happen near you (black cat) or even by abstract associations (the number 13); or possession of talismanic objects. Here I have used American examples but all cultures have their own superstitions. What makes such beliefs be superstition, of course, is that one can't point to any causal connection. I mentioned "future events", but believing that past bad luck was caused by a hex would be another superstition.

I don't have anything new to say on the topic; the book Believing in Magic: The Psychology of Superstition by Stuart Vyse gives a reader-friendly account of one psychologists's view.

2. Retrospective luck

A short definition of (good) luck is Most of us, looking at our individual past experiences, would find instances where we consider we were lucky or unlucky, and this is what I mean by "retrospective luck". The link goes to my analysis (which enlarges upon the comments below) of a discussion of luck in everyday life by the philosopher Nicholas Rescher. In particular, Rescher suggests the following taxonomy. On first reading this list I was skeptical -- the categories are somewhat vague and overlapping, and were based on hypothetical examples -- but they actually do well on real examples, at least after adding two more categories: All this refers to memorable instances of luck, rather than day-to-day instances of minor good or bad luck that we quickly forget.

3. Luck as seizing future opportunity

One of my favorite quotes is

This reminds us that the word chance is often used to mean opportunity, as in Here is a chance to invest in Ji'an's yam powder and forest frog fat (sic). But looking for discussion of the idea of maximizing your future opportunity leads one into a morass of "how to succeed in business" and pop-psych self-help books. One book that mostly avoids the morass is The Luck Factor by the psychologist Richard Wiseman. The book is based in part upon interviews with several hundred people who self-describe as being extremely lucky or unlucky. He expresses his conclusions as four principles with twelve subprinciples: the link goes to a complete list and my further analysis. My basic critique is that this (as implicit advice) isn't really about luck at all; any set of maxims on the topic "how adopting a positive attitude towards life will help lead to success" would include such advice. Anyway, it is interesting to contrast this psychologist's advice with the more "philosophical" advice by Rescher:

4. Separating skill from luck as contributors to success

xxx to be discussed elsewhere.

So what is luck, anyway?

The discussion above indicates the difficulty is saying what luck is; the word really is used with different meanings. But let us return to the context of "retrospective luck" and first repeat the earlier short definition of (good) luck: This reminds us that, in contrast to other words associated with chance, luck is almost always used in reference to an individual person. Everything we would call (good) luck fits (*), but not everything fitting (*) would be counted as luck, so can we refine (*)? Consider the following 4 characteristics of an event.
  1. it involves chance, in the particular senses of unpredictable and outside the control of the individual;
  2. it is unlikely;
  3. it has a substantial impact on the individual;
  4. it is an event that happens at a particular time (rather than an ongoing "state of affairs").
I regard these as determining the core concept of luck, in that
(i) almost any event with all 4 characteristics would be regarded as luck
(ii) Most iconic or hypothetical examples of luck, such as the linked list from Rescher, do indeed have all 4 characteristics.
It is easy to find examples without one of the last three characteristics that one would still call luck; I do not see any sharp borderline between this core notion and the overly broad notion (*).

Academic literature

A useful account of academic literature relating to luck is given in The psychology and philosophy of luck by D. Pritchard and M. Smith. But I am not convinced by their own attempt to capture the core notion of luck, which is The former is my (3). The latter just seems a rather confused way to say unlikely; or rather it is saying "unlikely, even conditional on knowing that everything not closely affecting the outcome". But I see no virtue in replacing the usual "conditional on what you know initially", implicit in any real-world discussion of chance, with a "possible worlds" story.