Discussion Arcs for Topics and Philosophers

Let's define a discussion arc in philosophy as a curve displaying how frequently a term appears in philosophical journal abstracts, titles, and keywords. Discussion arcs can reveal trends over time, as they come and go.

For example, "ordinary language" was a popular topic of discussion in the 1960s:

[click to enlarge and clarify]

My method: I searched for the term in the abstract, title, or keywords (subject) of articles in Philosopher's Index, in five-year chunks from 1940-1945 to 2021-2025.[1] I then divided the number of hits by a representative universe of hits for abstract or title containing "language", "epistemology", "mind", "metaphysics", "ethics", "moral", "political", "aesthetics", or "logic".[2]

By looking for distinctive terms or phrases connected to particular arguments, we can also track when an argument receives wide uptake. For example, Hilary Putnam's famous "Twin Earth" thought experiment, though originally presented in 1975, didn't receive much immediate uptake, receiving peak discussion in the 1990s:

We can also look for topical trends. If you think artificial intelligence is recently hot, you're right!

The figure also shows a smaller peak in the late 1980s, before the "AI winter" that has recently thawed.

Another thing you might see in the artificial intelligence arc, if you squint, is noise early in the data. This makes sense, since the early data have far fewer hits in the representative universe of articles containing one of the nine keywords: 457 articles in 1940-1945, compared to 33,552 in 2016-2020.

We can also examine the discussion arcs of particular philosophers. Note that "discussion" in the sense I've defined is very different from citation. A philosopher who is cited in passing might have very little influence on the shape of an article. In contrast, if a philosopher's name is explicitly mentioned in the title, abstract, or keywords, that philosopher's work is among the chief topics of the article. Discussion rates and citation rates thus capture different phenomena and will sometimes diverge.

Here are the arcs for the seven "most important Western philosophers of all time", according to a poll by Brian Leiter in 2017.

Notice how much discussion there was of Aristotle in the early 1940s! "Aristotle" alone gets more than a quarter as many hits as the broad disjunctive search for "language" or "epistemology" or "mind" or "metaphysics" or "ethics" or "moral" or "political" or "aesthetics" or "logic". Plato and Kant each also get almost as many as Aristotle.

Since then, there's been a steady decline in the proportion of articles mentioning these prominent historical figures. My sense is that this is due to two factors: first, the decline in the relative prominence of history of philosophy compared to other areas of philosophy; second, a shift within history of philosophy toward considering a broader range of traditions and figures, including non-Western traditions and women philosophers.

It's perhaps also interesting that Kant has declined less than the ancient Greeks, overtaking them as the most discussed philosopher.

I thought I'd finish today with discussion arcs of some more recent historical figures, who peak at different times:

Notice that Russell peaks in the 1940s to 1950s, during which period he is discussed almost as much as Aristotle, Plato, and Kant, who themselves are (as I noted above) discussed in a striking proportion of articles. There is a little false positive noise for Russell (some other people with "Russell" as a first or last name), but my estimate is that about 90% of hits are accurate.

Wittgenstein peaks in the late 1960s, Frege in the early 1980s, and Nietzsche in the early 2000s. Heidegger's influence is moderately steady from the late 1960s to the early 2000s, declining modestly in the past couple of decades.

Perhaps worth mentioning: These data cover a wide range of journals, regardless of prestige. In an analysis a few years ago, I found that the journals conventionally regarded as prestigious mention prominent "analytic" philosophers such as Frege, Wittgenstein, Quine, Chisholm, and Putnam much more frequently than prominent "Continental" philosophers such as Nietzsche, Heidegger, Sartre, Foucault, and Derrida: The analytic/Continental divide is alive and well. There might be other interesting trends to discover if we subdivide the universe of articles.

In a week or two, I'll do a follow up post looking at the discussion arcs of prominent philosophers born 1900-1945, partly to test my "age and fame" hypothesis: that philosophers tend to have their peak influence around ages 55-70.

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[1] The data begin in 1940, so I used a six-year chunk for the first period. As of Feb 27, data for 2025 are only about two-thirds complete and there are no data for 2026.

[2] This is not all articles, especially in the early period, where abstracts are less available. The idea is to roughly compensate for having fewer abstracts, and thus fewer opportunities for hits in the early data, by comparing the rate of appearance of the target terms with the rate of appearance of several, but not too many, widely used terms across a variety of philosophical topics.

Discussion Arcs

A philosophical discussion arc, as I'll use the term, is a curve displaying how often a topic or author is used as a "keyword" in a philosophical journal article or book abstract (i.e., in the article's or book's title, abstract, or list of key words). By looking at discussion arcs we can see what topics have been hot and what philosophers have been influential.

Let's begin with topical discussion arcs. On the x-axis is publication year, in five-year slices. The y-axis is a ratio: It's the number of articles in the Philosopher's Index containing the keyword, divided by a representative universe of articles, multiplied by 100. The data begin in 1940.

(A ratio is a much more accurate indicator of influence than is raw number, since the number of philosophy articles has increased about twenty-fold since the 1940s. I generated the representative universes, which serve at the denominators, by broad keyword searches, as indicated with each graph.)

Some topics have generated consistent interest over the decades. Dualism is one, as you can see below. The * is a truncation symbol, so this chart tracks any keyword starting with "dualis".

[Representative universe: language + epistemology + mind + metaphysics -- lemmings for short.]

Interest in the leading 17th and 18th century philosophers is also steady across the period (with perhaps Kant gaining discussion and Locke losing discussion):

[Representative universe: Lemmings + ethic* + moral* + polit*, or EMPlemmings for short]

Voguish topics, in contrast, are arc shaped.

Here, for example, is "twin earth" (a thought experiment about what the word "water" would mean in a world virtually identical to ours but with a different chemical formula for water):

[Representative universe: Lemmings]

And here is "ordinary language" (a way of thinking about philosophical issues popular in the middle of the twentieth century):

[Representative universe: Lemmings]

Here's a chart that displays the rise of Nietzsche from the second tier of historical figures into the first tier. (Note Nietzsche's final y-axis numbers are higher than those of Descartes, Locke, or Hume in the chart above.)

[Representative univerise: EMPLemmings]

Twentieth century philosophers also have arcs. Here are five influential philosophers born in the 1910s. Note that discussion of their work tended to peak at about age sixty, with the exception of Donald Davidson:

[Representative universe: Lemmings]

In fact, there's a fairly consistent pattern for the influence of 20th century analytic philosophers, as measured by discussion arc, to peak around age 55-70. The following chart shows average discussion-arc data from 26 prominent 20th century philosophers, with age on the x-axis. I normalized each philosopher's peak influence to 1. I did not truncate the philosophers' discussion arcs at death.

[Representative universe: Lemmings; all included philosophers are Lemmings specialists]

I find it interesting that influence tends to peak at age 55-70, while the age at which philosophers tend to do their most influential work is about 35-40. (Here's a preliminary discussion of that last point; I hope to have fuller data on the matter soon.) I guess it takes time for word to get around!

Update, May 12:

In this more recent post, I (mostly) retract my claim about the age at which the most influential philosophical work tends to be done. Check out this cool chart!

Discussion Arcs of APA Presidents from the 1970s

One of the highest forms of recognition a philosopher in the U.S. can receive is the presidency of an APA division. Lists of the APA divisional presidencies thus provide information, not filtered through current lenses, of people who were regarded as prominent philosophers in their day.

If, like me, you have a kind of morbid curiosity about the fleetingness of academic fame, you might wonder what becomes of these divisional presidents. Lists from the 1930s and 1940s are almost entirely names I don't recognize: Albert Perly Brogan? Marten ten Hoor?

In several past posts, I have used the concept of a "discussion arc". A discussion arc for a topic or a philosopher is simply the number of times the topic or philosopher appears in a keyword search (including title and abstract) in the Philosopher's Index, divided by some representative number of the universe of articles. Some topics and philosophers have fairly steady rates of discussion over the decades (dualism, Kant); others show sharp temporal peaks (ordinary language, Chisholm). I have found that, in general, twentieth century Anglophone philosophers' discussion arcs tend to peak at around age 55-70.

The three divisions (Eastern, Central, Pacific) had a total of 30 presidents in the years ending 1970-1979. I excluded from analysis nine presidents with last names generating too many false positives in keyword searches.[note 1] Of the 21 remaining presidents, six achieved discussion rates of over five per thousand articles (from a representative universe of articles [note 2]). For analysis, discussion is broken into five-year chunks. Click for a clearer view of the figure below:

Around 1975, most of this group had similar discussion rates (though John Rawls rather more). Most arcs show the typical hump shape with peaks at around ages 55-70. The declines of Jaakko Hintikka and especially Norman Malcolm (both of whom peaked a bit young) are notably more severe than the others.  Rawls and Wilfrid Sellars show bimodal distributions, with the typical late-career peak followed by a more recent resurgence.

A second group of five philosophers had peak discussion rates between 1.5 and 5 per thousand (again click for clarity):

Although the data are noisier, as one might expect with fewer data points, all five show the typical hump-shaped arc, though Stuart Hampshire peaks a bit earlier than typical and Alan Gewirth a bit later. Paul Grice appears to have had considerably more staying power than the others, though his recent discussion rate of about 1.5 remains lower than all in the first group except Hintikka and Malcolm.

Four more 1970s APA divisional presidents, while peaking below 1.5, still continue to draw a bit of discussion, with William Alston and Patrick Suppes recently exceeding all in the mid-tier group except Grice.

Finally, there's a group of six who together have drawn only three keyword hits since the year 2000:

Could we have predicted these results in the 1970s? Yes! If we average the discussion arcs of the four tier groups, the overall trend is clear: The much-discussed remained much discussed, the less discussed remain less discussed:

In fact, the decline is much less sharp, on a percentage basis, for the Tier 1's than for the lower tiers, which might be partly explained by my hypothesis about the Winnowing of Greats.

The spread also seems to be clearly evident by the early 1960s, when these philosophers were in their early 40s to early 50s -- maybe even earlier. We can to a substantial extent predict discussion rates in the 2000s, among APA division presidents from the 1970s, based on those presidents' discussion rates in the five-year span during which they turned 45. If we rank their age-mid-40s discussion rates and also rank their discussion rates since 2000, the ranks correlate at r = .59 (p = .006). Nine of the 21 are ranked very near their age-mid-40's discussion ranks (within 2) and 13 are within 4. The biggest outliers are Malcolm (fell from 2 to 12), Donald Davidson (rose from 12 to 2), and Grice (rose from 14 to 5).

Notes:
1. William Thomas Jones, John Wisdom, Lewis White Beck, Alonzo Church, William Henry Hay, Ruth Barcan Marcus, Kurt Baier, Wesley Charles Salmon, and William Craig.  Also: I hand-culled false positives in any five-year period in which the target philosopher generated 40 or fewer keyword hits on a truncation-symbol appended version of his last name (e.g., Lazerowitz*); for those with 40 or more keyword hits, I spot-checked for problematic patterns.

2. Search term: KW=ethic* or KW=moral* or KW=politic* or KW=language* or KW=epistem* or KW=mind* or KW= metaphys*.

Age and Fame in Philosophy

A philosophical discussion arc is a curve displaying how frequently a term appears in philosophical journal abstracts, titles, and keywords (compared to a representative universe of common philosophy words). A couple of weeks ago, I posted discussion arcs from the 1940s-2020s for several topics and historical philosophers.

Today, I want to use them to explore my age and fame hypothesis: that philosophers tend to have peak influence at around ages 55-70. Jerry Fodor, for example, received a lot of discussion in the early 1990s, but recently much less:

Fodor was a peaky philosopher in the following sense: His peak discussion rate (1.05%) is much higher -- 12 times higher -- than his recent discussion rate (0.09%).

John Rawls, in contrast, is considerably less peaky (so far), peaking at only 2.7 times the current rate, despite having more time to decline:

Both Fodor and Rawls peak in their late 50s, fitting the pattern I've seen in previous analyses (here and here) that philosophers tend to reach their peak influence around age 55-70.

For today's post I decided to create discussion arcs for 25 philosophers who are highly cited in the Stanford Encyclopedia of Philosophy: twelve from the Not-So-Silent Generation in philosophy, born 1928-1945, and thirteen from the generation born 1900-1927. I chose the most SEP-cited philosophers from each generation, excluding ones whose last names generate noisy results (sorry, no David Lewis or Bernard Williams). I'll show you their discussion arcs, then do a composite analysis of discussion by age. The charts are a little crowded and blurry on some browsers; clicking on them might work to clarify and enlarge.

Here's the first group:

Some observations:

• Ayer peaks relatively early, but even so, there's significant delay between the publication of his most influential book in 1936, when we was only 26 years old, and peak discussion in the late 1950s, about twenty years later.
• Quine and Popper peak later, in the 1970s, when Quine is in his mid-60s and Popper is in his late 70s.
• All the authors are trailing off by the 2010s, though Quine, Popper, and Tarski less so than the others.

Here's a second group:

• Notice that the vertical axis for this group doesn't rise quite as high as for the previous group, so the scaling isn't the same.
• Dummett has peaks both in the late 1950s (for his early work on causation) and the early 1980s (discussing a wide range of work in metaphysics and philosophy of language).
• Although Anscombe's peak is early, in the early 1960s when she was in her early 40s, unlike any of the other authors, her discussion rate has been steadily rising over the past few decades.

Group three:

• The vertical axis for this group is still lower: Kripke at his peak wasn't as proportionally much discussed by this measure as were Quine or Rawls at their peaks. It's possible that this reflects a flaw in my method. Later in the database, abstracts are more available and longer, and although I attempted to compensate for this by comparing with search result for terms like "mind", "language", and "ethics", it's possible I overcompensated. However, it's also possible that this trend toward lower peaks with younger authors is real. As the field grew larger, there may have been less room for a few thinkers to dominate it as thoroughly.
• Kripke, Nozick, and Searle peak relatively early, compared with most philosophers I have examined -- in the 1970s, when they're in their late 30s to early 40s.
• Though Stalnaker also peaked in the late 1970s, when he was in his late 30s, like Anscombe his has risen in recent decades, and in 2021-2025 he is almost back to his earlier peak.

Finally:

• These authors have had the least time to decline from their peaks. But their discussion rates of .001 to .004 in 2021-2025 are comparable to those from earlier generations (and substantially less than Kripke and Rawls), which suggests that they might have relatively less staying power.
• You'll probably also have noticed it’s a much narrower age band than the others. There's a high density of Silent Generation philosophers cited in the Stanford Encyclopedia, for reasons I discuss here.

In the following graph, I've aggregated discussion rates by age across all of the included authors, with five-year smoothing:

Broadly in line with my previous work, the average peak is in the early 50s to the late 60s -- though as you can see from the graphs above, there's considerable individual variation. Overall, the results might trend a little bit earlier than what I've seen in other analyses, but not by much.

As I've noted elsewhere, peak influence is often a couple of decades after the thinker's most influential work. For example (besides Ayer as described above), Kuhn's and Popper's peaks in the late 1970s were 15-20 years after Kuhn's Structure of Scientific Revolutions and about 20 years after the English translation of Popper's Logic of Scientific Discovery.

The Rise and Fall of Philosophical Jargon

In 2010, I defined a discussion arc, in philosophy, as a curve displaying the relative frequency at which a term or phrase appears among the abstracts of philosophical articles. Since then, I've done a few analyses using discussion arcs, mostly searching for philosophers' names (here, here, here, here, here).

Today I thought it would be fun to look at philosophical jargon -- its rise and fall, how much it varies over time, and as a measure of what is hot. Maybe you'll find it fun too!

I rely on abstract searches in The Philosophers Index. NGram is nifty, but it doesn't do well with trends specifically in academic philosophy (see here). JStor is interesting too, but it's a limited range of journals, especially for articles less than six years old.

First, I constructed a representative universe of articles (limiting the search to journal articles only): In this case, I searched for "the" in the abstracts, in five year intervals from 1940-present, except merging 1940-1949 for smoothness and a large enough sample. Then I searched for target terms in abstracts in the same five-year intervals. I constructed the curves by dividing the number of occurrences of the target term by the number of articles in the representative universe in each period.

Some topics and terms are perennial, rising and falling a little, but not in any dramatic way. Others increase or decrease fairly steadily without a clear peak (allowing for some noisiness especially in the early data). For example, here are the are the arcs for happiness, Kant*, and skepticism or scepticism (all three fairly steady), evolution* and democra* (both rising), and induction (falling):

(The asterisk is a truncation symbol; the y-axis is percentage of all abstracts containing the word.)

[apologies for blurry image; click to enlarge and clarify]

(You thought happiness was more important to philosophers than Kant? Wrong!)

One way to measure how trendy or steady a topic is, is the ratio of percentage of discussion in its peak period, compared to its average discussion. Exactly equal discussion over the whole period would yield a ratio of 1:1. Fairly steady discussion with some noise would be 1 to 1.5. Topics that rise and fall more substantially would be proportionally higher. Call this the Max/Average Ratio. For the six topics above, the Max/Average Ratios are:

Kant*: 1.3

happiness: 1.4

skepticism or scepticism: 1.4

evolution*: 1.5

democra*: 2.0

induction: 3.0

Evolution*, though it approximately triples over the period, has a Max/Average Ratio not too far from one. Democra* rises from a substantially lower level of discussion than does evolution* and has a higher Max/Average Ratio. Induction crashes down to about a sixth of its initial level of discussion (0.174% in the first four periods to 0.028% in the final two) -- hence its moderately large ratio.

Now let's consider some jargon terms that more clearly reflect hot topics.

Since the scale is logarithmic, periods of zero incidence are not charted. Also remember that logarithmic scales visually compress peaks relative to linear scales. For example, though the decline of "language of thought" is not so visually striking, usage was in fact about seven times as much at peak as it is now.

"Grue" was introduced by Nelson Goodman to describe a puzzle about how we know the future in his "New Riddle of Induction" in 1955. As you can see from the chart, discussion peaked 10-15 years later, in the late 1960s. "The original position" was introduced by John Rawls in his 1971 A Theory of Justice, describing part of an idealized decision-making process, and discussion of it peaked in the late 1980s, about 15 years later. "Supervenience" has a murkier origin, but was popularized in philosophy by R.M. Hare in 1952, to talk about how one set of properties might covary with another (for example the moral and the physical). Discussion peaked about 40 years later in the early 1990s. Hilary Putnam introduced "Twin Earth" (a planet with XYZ instead of water) in a thought experiment in 1975, and discussion peaked 15-20 years later in the early 1990s. "Radical interpretation" was introduced by Donald Davidson in the early 1970s, peaking 15 years later in the late 1980s. Finally, the "language of thought" was introduced by Jerry Fodor in his 1975 book of the same title, peaking 15-20 years later in the early 1990s.

With the exception of supervenience -- maybe partly because the concept took some time to transition from ethics to the metaphysics of mind -- the pattern is remarkably consistent, with peaks about 15-20 years after a famous introduction event. This pacing reminds me of my earlier research suggesting that individual philosophers tend to receive peak discussion around ages 55-70, despite producing their most influential work on average about 20 years earlier (NB: the two data sets are only partly comparable, but I'm pretty sure the generalization is roughly true anyway). This is the pace of philosophy.

For these terms and phrases, the Max/Average Ratios are a bit higher than for the rising and falling topics sampled above:

superven*: 2.7

"radical interpretation": 3.4

"Twin Earth: 3.9

"the original position": 4.2

"language of thought": 4.6

grue: 5.3

The Max/Average Ratio, of course, doesn't really capture rising and falling; and the ratio will be inflated for more recently introduced terms, assuming virtually zero incidence before introduction.

For a better measure of peakiness, we can examine the ratio of the maximum discussion to the average discussion in the first two and final two time periods. To avoid infinite peakiness and overstating the peakiness of rare terms, I'll assume a floor level of discussion of .01% in any period. Call this Peakiness with a capital P. Five of the six topics in the first group have a Peakiness between 1.3 and 2.0, and evolution* has 2.9.

In contrast:

superven*: 3.8

"Twin Earth": 4.7

"radical interpretation": 6.3

"the original position": 8.4

"language of thought": 8.8

grue: 50.6

Grue was hot! Although its peak discussion was about the same as superven*, it has crashed far worse -- or at least it has, so far. If we had a longer time period to play with, we could try to make the analyses more temporally stable by sampling a window of 50 years before and after peak, thus giving superven* more of a fair chance to finish its crash, as it were.

Okay, how about newer jargon? Let's try a few. I guess first I should say that jargon is wonderful and valuable, and I actually love the grue and Twin Earth thought experiments. Also some jargon becomes a permanent part of the discipline -- such as "dualism" and "secondary qualities". Maybe grue and Twin Earth will also prove in the long run to be permanent valuable contributions to the philosopher's toolbox, just in a lower-key way than back when they were hot topics. I don't really mean "jargon" as a term of abuse.

In 1974, Robert Kirk introduced "zombies" in the philosophical sense (entities physically indistinguishable from people but with no conscious experience), but usage didn't really take off until they got discussion in several articles in Journal of Consciousness Studies in 1995 and in David Chalmers' influential The Conscious Mind in 1996. Contrary to popular rumor, the zombie doesn't appear to be dead quite yet. "Epistemic injustice" was introduced by Miranda Fricker in the late 1990s and early 2000s. "Virtue epistemology" was introduced by Ernest Sosa in the early 1990s. Fictionalism has a longer and more complicated history in logic and philosophy of math.

The "explanatory gap" between physical or functional explanations and subjective conscious experience was introduced by Joseph Levine in 1983, but doesn't hit the abstracts until some papers of his in the early 1990s. "Experimental philosophy" in its earlier uses refers to the early modern scientific work of Newton, Boyle, and others. It's recent usage to refer to experimental work on folk intuitions about philosophical scenarios hits the abstracts all at once with five papers in 2007. Consistently with my twenty-year hypothesis, of these, "explanatory gap" is the only one that shows signs of being past its peak (despite hopes expressed by some of my Facebook friends). Maybe fictionalis* is running longer.

Okay, I can't resist trying a few more discussion arcs, just to see how they play out.

"Possible worlds" goes back at least to Leibniz, but its first appearance in the abstracts was by Saul Kripke in a 1959 article. It peaks at 2.0% in the late 1960s, but has enduring popularity (currently 0.4%). "Sense data" as the objects of perception was introduced in the early 20th century by G.E. Moore and Bertrand Russell and has lots of discussion in the beginning of this dataset (1.7%), crashing down to levels appropriate to a historical relic (0.02%). "Qualia" has a couple occurrences early in the abstracts and traces back to C.S. Peirce in the 19th century, then hits the abstracts again with an article by Sydney Shoemaker in 1975, peaking in the late 1990s.

Supererogation (morally good acts beyond what is morally required) entered modern discussion in the late 1950s and early 1960s (first hitting the abstracts with Joel Feinberg in 1961), then peaked in the late 1980s -- but it looks like it might be staging a comeback? Wittgenstein introduced the idea of the "language game" in his posthumous Philosophical Investigations (1953), with discussion peaking in the late 1970s. Thomas Nagel introduced "moral luck" in a classic 1979 article, and although it peaked in the late 2000s, it hasn't yet declined much from that peak.

Possible worlds has the highest Peakiness of the lot -- though nothing like grue -- at 8.4. "Language game" is next at 5.1. The rest aren't very Peaky, ranging from 2.1 to 2.9.

I've spent more hours this week doing this than I probably should have, given all my other commitments -- but there's something almost meditative about data-gathering, and the arcs yield a perspective I appreciate on the historical brevity of philosophical trends.

Chinese Philosophy Discussion Arcs

Different classical Chinese philosophers have drawn different amounts of discussion in the Anglophone world over the past seventy years.  I want to look at this phenomenon quantitatively and then suggest a general conjecture about the history of philosophy.

The six target philosophers include two who are well-known in the Western world outside scholarly circles, Confucius and Laozi (aka Lao Tzu), and four who are much less well known, Mencius, Zhuangzi, Xunzi, and Mozi (aka Mengzi, Chuang Tzu, Hsün Tzu, and Mo Tzu).  Below is a graph of their "discussion arcs" -- that is, the rates, times 1000, at which their names appear in keyword (including abstract and title) searches in Philosopher's Index, divided by a representative universe of articles. Click the image for a clearer view.

(For more details on discussion arcs, see here and here. My search terms also included many less common early spellings such as Mocius and Chuangtze.)

One result that jumps out is (as one might expect) the relative prominence of Confucius. Also striking, though, on closer inspection, is another phenomenon: The relative decline of Confucius and Laozi compared to the other four philosophers. To better display this trend, here's a comparison of the proportion of articles mentioning Confucius or Laozi to the proportion mentioning any of the other four. (Again, click for clarity.)

I don't interpret as meaningful the apparently very tight match of the lines at the end of the graph -- but the approximate match does seem meaningful. In the 1940s-1970s, Confucius and Laozi combined received about twice as much discussion as the other four philosophers combined. Starting in the 1980s or 1990s, that situation changed.

My general conjecture is this: As a subfield in the history of philosophy matures (as I believe the history of Chinese philosophy has done in the past couple decades), proportionately less expository attention is devoted to the most famous headline figures and proportionately more attention is devoted to less well known figures. This is a kind of "winnowing of the greats" in reverse.

If that conjecture is correct, we ought to see the same effect in other subareas of the history of philosophy.

Heidegger and Wittgenstein Break Away from the Pack

A philosophical discussion arc (as discussed in Tuesday's post) is the trend, over time, in the use of a term or name as a keyword in philosophy articles and books. As I mentioned Tuesday, discussion of prominent philosophers' work tends to peak around age 55-70. However, not all philosophers show this trend.

Given that the dataset starts in 1940, the only age cohort suitable for examining breakaways -- philosophers whose discussion arcs continue to rise after age seventy -- is the cohort born around the year 1900. Only for that cohort do we have both peak-career discussion rates and later discussion rates in the dataset.

I examined the discussion arcs of eight leading philosophers born between 1885 and 1915: Wittgenstein, Heidegger, Carnap, Ryle, Popper, Sartre, Merleau-Ponty, and Quine. On the x-axis is date, in five-year slices. On the y-axis is a ratio: The number of times the philosopher's name appears as a keyword, divided by a broad index of philosophical keywords in the database, times 100. Five of these philosophers show the usual career arc:


Heidegger and Merleau-Ponty, however, and maybe Wittgenstein, seem to show a different pattern:


To see more clearly how Heidegger and Wittgenstein broke away from the pack, let's remove the clutter by taking averages:


From about 1940-1954, Heidegger, Wittgenstein, Carnap, Ryle, Popper, Sartre, and Quine were all receiving about an equal amount of discussion. But only Heidegger and Wittgenstein increased and sustained that level of discussion in the ensuing decades.

In the previous generation of philosophers, we seem to see the tail end of a similar story, with Frege and Husserl breaking away while Royce, Bergson, Dewey, and Whitehead decline (though declined Dewey is still discussed as much as is broken-away Frege).

How Prominently Is Women's Philosophical Work Discussed? One Empirical Measure

Citation is one thing. Discussion is another. You can drop a reference without really engaging someone's work (e.g., Snerdfoot 2011). But as Helen de Cruz has emphasized, discussing a possible Bechdel test for philosophy papers, citation analysis is insufficient as a measure of serious engagement with someone's work. I propose two rough measures of "discussion".

"Discussion" itself I operationalize as follows: A person is discussed if that person's name appears in the abstract of an article. Looking at the Philosopher's Index database, I have examined discussion arcs over time for various well-known philosophers in a series of blog posts (e.g., here, here, here, here).

"Extended discussion" I operationalize as follows: A person receives extended discussion if that person is referred to at least twice in the abstract of the article, by either name or pronoun. The nominative pronoun might be especially telling, since its presence suggests that the person is being referred to repeatedly in independent clauses. For example:

Later, Nussbaum gradually reconsidered the notion of patriotism in texts that remained largely unknown and rarely discussed. This article begins with a brief account of her shift from cosmopolitanism to what she terms 'a globally sensitive patriotism,' and the task assigned to education within this framework....

This suggests a possible rough and simple measure of the relative rates at which women receive extended discussion in philosophy articles compared to men: Compare the ratio of "he" to "she" in philosophy abstracts, then remove cases in which those words are used with generic intent (e.g., "If the agent wouldn't have done otherwise whether or not she could have....") or otherwise not referring to an individual philosopher whose work is being discussed (e.g., reference to historical leaders, or third-person references to the author herself for abstracts written in the third person).

Method:

I searched Philosopher's Index for all appearances of "he" or "she" in abstracts from 1970 to the present in a sample of ten ethics journals and ten general philosophy journals. [See Note 1 for journal details.] This yielded a total of 2321 abstracts. I then skimmed each abstract to remove all cases in which the pronoun was not used to refer to a specific philosopher whose work was being discussed. [Yes, I looked at over 2000 abstracts! Obviously, my determinations had to be quick, but in almost every case it could be made confidently within just a few seconds.] To examine temporal trends, I grouped results by decade. I also separated citations of pre-20th-century historical figures from 20th and 21st century figures.

Results:

Percentage of recipients of extended discussion (as measured by nominative pronoun use in abstracts) who are women:

1970s
Ethics: 8/92 (9% women) [so 91% of those receiving extended discussion are men]
General journals: 4/134 (3%)

1980s
Ethics: 3/77 (4%)
General: 0/137 (0%)

1990s
Ethics: 20/147 (14%)
General: 9/189 (5%)

2000s
Ethics: 16/184 (9%)
General: 16/229 (7%)

2010s
Ethics: 19/120 (16%)
General: 27/244 (11%)

Merging the ethics and the general journals, so far in the 2010s, approximately 13% of philosophers receiving extended discussion in these journals are women.

In contrast with my earlier data on authorship in the most elite journals, this does appear to be a statistically significant increase since the 1970s (5% vs. 13%, z = 3.2, p = .001).

If we remove discussion the pre-20th century figures (Kant, Plato, etc.), then numbers look like this:

1970s
Ethics: 8/64 (13% women)
General journals: 4/97 (4%)

1980s
Ethics: 3/54 (6%)
General: 0/106 (0%)

1990s
Ethics: 19/94 (20%)
General: 9/144 (6%)

2000s
Ethics: 15/140 (11%)
General: 16/184 (9%)

2010s
Ethics: 18/95 (19%)
General: 26/210 (12%)

Still only 14%!

(Since ethics is a minority of the discipline, it makes sense that the center of gravity would be closer to the general journals.)

These numbers are consonant with two other measures I've done that suggest that at the very highest levels of prestige our discipline is still predominately male.

Among the 267 most-cited contemporary philosophers (in the Stanford Encyclopedia of Philosophy) only 10% are women.

About 13% of authors in the most elite philosophy journals are women.

For the discipline as a whole, percentages of faculty in the 21st century are typically in the low 20%'s (U.S. data here).

The outlier analysis here is my analysis of American Philosophical Association meetings, where women were 35% (144/413) of the invited symposium speakers on the main program, and 32% of main program participants overall.

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Note 1: Ethics and non-ethics were analyzed separately because previous analyses have found differences by area, and because journals divide fairly naturally into those specializing in ethics/political, "general" journals that publish proportionately little ethics, and other types of specialty journals (like philosophy of science).

Ethics journals were the top ranked journals in surveys by Brian Weatherson and Brian Leiter (excluding the non-ethics journals appearing in the latter) and include Ethics, Philosophy & Public Affairs, Journal of Political Philosophy, Utilitas, Social Philosophy and Policy, Journal of Ethics, Ethical Theory & Moral Practice, Journal of Social Philosophy, Journal of Value Inquiry, and Journal of Moral Philosophy.

The comparison list was a stratified sample of "general" philosophy journals drawn from Leiter's surveys here and here and included Nous, Midwest Studies in Philosophy, Synthese, Mind, Philosophical Studies, Proceedings of the Aristotelian Society, European Journal of Philosophy, Dialectica, Philosophical Topics, and Theoria. The sample was stratified so that the selected journals would not differ too much in overall prestige from the ethics journals. ----------------------------------------------------------

For a related post, also including discussion of the use of "he" and "she" and generic pronouns, see Use of "She" and "He" in Philosopher's Index Abstracts (Sep. 16, 2014). See also Kieran Healy's nice analysis of gender citation patterns in four leading philosophy journals.

The Forty Most-Cited Contemporary Authors in the Stanford Encyclopedia of Philosophy

As part of my background work on discussion arcs, I compiled all the bibliographic entries in the Stanford Encyclopedia of Philosophy, excluding the purely historical entries, and I noted which philosophers were cited in the most different entries.

(Some obvious shortcomings of the method: It favors breadth of influence over depth, the distribution of entries might differ from the distribution of philosophical research energy, and it might favor the perspectives and writings of the SEP editors. My aim, I should emphasize, is to generate a list of people whose discussion arcs might be interesting, not to generate a definitive measure of philosophical prominence. I'm sure I have also made some coding errors; corrections welcomed.)

With those caveats, then, here are the top forty contemporary philosophers on the list (in parens are the number of SEP entries citing them; I examined 664 SEP entries in total; "contemporary" means born 1900 or later).

1. Lewis, David (162)
2. Quine, W.V.O. (133)
3. Rawls, John (95)
4. Davidson, Donald (93)
5. Putnam, Hilary (88)
6. Kripke, Saul (84)
7. Armstrong, David (72)
7. Nagel, Thomas (72)
9. Fodor, Jerry (70)
10. Dennett, Daniel (69)
10. Jackson, Frank (69)
10. Williams, Bernard (69)
13. Nozick, Robert (68)
13. Searle, John (68)
15. Chisholm, Roderick (67)
16. Harman, Gilbert (60)
17. Dummett, Michael (58)
18. Dworkin, Ronald (57)
19. Nussbaum, Martha (55)
19. Raz, Joseph (55)
19. Van Fraassen, Bas (55)
22. Dretske, Fred (54)
22. Van Inwagen, Peter (54)
24. Chalmers, David (52)
24. Goldman, Alvin (52)
24. Kitcher, Philip (52)
27. Goodman, Nelson (51)
28. Strawson, P.F. (50)
29. Parfit, Derek (49)
29. Sober, Elliott (49)
31. Stalnaker, Robert (48)
32. Williamson, Timothy (47)
33. Geach, Peter (46)
33. Scanlon, T.M. (46)
35. Burge, Tyler (45)
35. McDowell, John (45)
37. Mackie, J.L. (44)
38. Plantiga, Alvin (43)
39. Adams, Robert (42)
39. Gibbard, Allan (42)
39. Lycan, William G. (42)

I find one omission particularly striking: Thomas Kuhn, cited in only 29 entries. (Karl Popper is a near miss at 37 entries.) Kuhn's omission probably reflects, in part, the SEP's underweighting of issues in general philosophy of science; it probably also reflects this measure's favoring of breadth over depth of influence.

The absence of "continental" figures like Foucault (13 entries) and Sartre (23 entries) reflects the generally "analytic"/anglophone pespective of the SEP (though Foucault and Sartre do have historical entries devoted to them).

Comparing these results with Brian Leiter's informal survey last year, the top three results are the same (setting aside Wittgenstein, Russell, and Heidegger, who are not "contemporary" by the present standard), though Leiter has Rawls beating Quine.

UPDATE, May 7:

Let me emphasize that I excluded historical entries, so historians of philosophy will be underrepresented in the data. Also, the SEP bibliographies strongly favor recent work, with the work from the year 2000 being the most cited (cited 2.5 times as often as the year 1980, for example). Here's a chart of citation year in the SEP:

That might be another factor influencing the poor showing of Kuhn (whose most cited work was in 1962) and, as Brian Leiter points out, of Hart, whose most cited work was in 1961 -- though Quine (1960) still does very well.

SECOND UPDATE, May 7:

I have expanded the list to 200.

The Popular Persistence of Fading Philosophers

Late last year, Jean-Baptiste Michel and co-authors made public the Google Books Ngram Viewer, which graphically displays the rates at which words appear in the Google Books database over time. So, for example, one might compare Descartes vs. Nietzsche in English (click to enlarge):

or in German:

Pretty cool! We see Nietzsche (red) overtake Descartes (blue) in English. Plato (green) kicks butt in English, but does much more poorly in German while Kant (yellow) kicks butt in German and only recently challenges Plato in English. (Note: Using "Platon" in German. Merging with "Plato" in German raises Plato to almost the level of Nietzsche.)

Now, earlier in 2010, I had run a series of posts on what I call "discussion arcs", using as my measure the rate at which terms appear in keyword searches in the Philosophers Index database, over time. Naturally, it occurred to me to wonder whether the Ngram would deliver similar results.

It does not.

Some obvious differences are Ngram's broader expanse of time and the difference between the whole universe of books as a database vs. just philosophy sources -- especially the potential swamping of philosophy sources with non-philosophy sources. But even if we confine the search terms to names of philosophers that are distinctive enough so that we can assume that the references are mostly to those specific philosophers, there are important differences between the results.

Here's one: In one post, I noticed that most philosophers tend to have peak discussion in the Philosophers Index around age 55-70, while others (like Heidegger and Wittgenstein) seem to break away from the pack, without slumping in discussion. See these two graphs of fading philosophers:

Interestingly to me, these same "fading" philosophers -- at least the ones with canonical first-last name combos of the sort necessary for Ngram searchability -- do not fade appreciably in the Ngram results (again please click for viewability):

My interpretation: Not only is there an understandable delay between when a philosopher earns discussion by peers and when that discussion spreads into the universe of books as a whole, but there is an even more substantial delay between when philosophical discussion fades and when that fading begins to register in the universe of books as a whole. Philosophy of science is much less about Popper now than it was in the 1970s, despite the Ngram graph. And Josiah Royce? Most contemporary philosophers know him only as someone who used to be a famous American philosopher; few could, I suspect, name even one of his works or positions.

[Updated March 7]

The Rise of Ethics and Feminism

A philosophical discussion arc, as I defined the term a couple weeks ago, is a curve showing changes over time the use of a name or a word as a "keyword" in philosophy books and articles listed in The Philosopher's Index (which dates back to 1940).

Previous posts showed discussion arcs of various prominent philosophers. But I've also been searching by topic and subfield. One striking general result I've found is the rise of discussion in ethics relative to other philosophical subfields.

Here's a chart of the enormous increase in total rate of philosophical publication since the 1940s, with keyword searches related to subfield. (Note that the y-axis is scaled logarithmically. Note also that "*" is a truncation symbol, so that (for example) ethic* returns "ethic", "ethics", "ethical", etc. The rate of increase in the 1940s is somewhat inflated by the increase in the length of listed article abstracts.)

[If this or any other chart displays incorrectly, click on it to bring up a cleaner jpg.]

I don't know whether to find it alarming or exciting that if trends continue philosophers will soon be producing 100,000 articles and books per five-year period in some subfields.

What I am interested in here is not so much the absolute numbers, though, as the relative numbers. And not even the relative numbers per se, which may be somewhat misleading (since not all and only epistemology articles contain epistem* as a keyword, and the keyword false negatives and positives may differ by subfield), but rather the changes over time in relative numbers. In the chart above, for example, you will see that in the 1990s ethics (EMP: ethics, moral, political) crossed lemmings (language, epistemology, metaphysics, and mind). Assuming relatively constant false negatives and positives over time within each subfield, the crossover suggests that ethics has been growing faster than has language, epistemology, metaphysics, and mind.

The following chart displays that fact more clearly:

In the 1950s, about half as many books and articles had an ethic*/moral*/polit* keyword as a language*/epistem*/metaphys*/mind* keyword. Now there are more EMPs than lemmings.

Nor have other major subfields fared better, as you can see below:

The ethicists are taking over! (If only they would behave better.)

Feminism is now a major philosophical research specialization, as was not the case before the 1970s. The chart below displays its explosive rise. (In the denominator is EMPlemmings: all articles using any of the EMP or lemmings keywords.) Notice that the rise is almost entirely in the 1970s to early 1990s. The trend has been flat to declining since then.

The same chart shows a U-shaped curve for discussion of race. I double-checked a sample of the 1940s articles to see if they really did treat race or ethnicity as a substantive topic (rather than, say, using a phrase like "the human race" in the abstract simply to mean people), and almost all did use "race" in the intended way. In the context of World War II, race was I suppose a rather hot issue! Interesting that it should be less so, at least in the philosophy journals, in the heyday of the civil rights movement.

Distribution of Subspecialites among Anglophone Research Philosophers

As background for my work on discussion arcs, I've analyzed the distribution of research interests among research-oriented philosophers. Maybe some readers will find the data interesting.

My sample of research philosophers is non-emeritus professors with their primary appointments in Leiter top-20 ranked Anglophone philosophy departments -- 548 professors total, by my count. I noted the areas of research interest these professors listed on their departmental websites. Most philosophers listed about three to seven areas.

First, I looked at area of specialization, counting only the first listed area:

Then I looked at all listed areas of interest:

I also broke down historical interest by time period (splitting out Asian as a separate category):

Two things jump out at me from these data: first, the almost complete lack of interest in Asian philosophy among Leiter top-20 faculty; and second, the much greater rate of interest in metaphysics and epistemology than specialization in them. Here is a chart displaying the ratio of interest to specialization in the various subfields.

Almost five times as many philosophers list epistemology among their areas of research interest as list it as their first area of specialization. Philosophy of action shows an even higher ratio, though the total numbers are smaller. In contrast, philosophers tend not to express research interest in ethics or philosophy of science unless they list them as their first specialization.

On Continental Philosophy:

I also looked at interest in "continental" philosophy -- that is, interest in 19th and 20th century figures in the German-French tradition, like Hegel, Nietzsche, Heidegger, Foucault, and Derrida. Although top-ranked Anglophone departments have a reputation for hostility to 19th and 20th century continental philosophy, 45 philosophers (8.2%) listed continental philosophy or a continental figure among their research interests, an average of 2.3 philosophers per department. About 20% of Anglo-American research philosophers who express a research interest in any area of history of philosophy express a research interest in continental philosophy.

The Not-So-Silent Generation in Philosophy

The Silent Generation (born 1928-1945) is disproportionately represented among the most-cited authors in the Stanford Encyclopedia of Philosophy. Let's look at the numbers and think about why.

Background: This post is based on my analyses of citation rates in the Stanford Encyclopedia in 2010, 2014, 2019, and 2024. As a measure of prominence in (as I call it) "mainstream Anglophone philosophy", no measure has better face validity than SEP citation rates. For example, in my most recent analysis, the top five are David Lewis, W. V. O. Quine, Hilary Putnam, John Rawls, and Saul Kripke -- a much more plausible top 5, if the aim is to capture influence in mainstream Anglophone philosophy -- than top five lists from, say, Scopus, Google Scholar, or PhilPapers.

The Ten Most-Cited Philosophers, Generation by Generation

[update 12:49 pm: Some of the ranks below were incorrect due to a problem with the tie-counting algorithm I used today. This does not affect the analysis or August's original rankings. HT Daniel Nolan for the catch.]

"Greatest Generation" (born 1900-1927):

2. Quine, Willard van Orman (213)
3. Putnam, Hilary (190)
4. Rawls, John (168)
7. Davidson, Donald (151)
16. Strawson, Peter F. (116)
23. Dummett, Michael A. E. (110)
26. Armstrong, David M. (106)
26. Chisholm, Roderick M. (106)
34. Popper, Karl R. (94)
35. Goodman, Nelson (90)

The initial number before their name indicates their ranking in the most recent analysis, the number in parentheses indicates the number of main-page SEP entries in which they are cited.

"Silent Generation" (born 1928-1945)

1. Lewis, David K. (307)
5. Kripke, Saul A. (159)
8. Williams, Bernard (146)
10. Nagel, Thomas (137)
11. Nozick, Robert (135)
12. Jackson, Frank (130)
13. Searle, John R. (120)
14. Van Fraassen, Bas C. (117)
16. Harman, Gilbert H. (116)
18. Fodor, Jerry A. (115)

"Baby Boomers" (born 1946-1964)

6. Williamson, Timothy (152)
9. Nussbaum, Martha C. (140)
19. Fine, Kit (112)
24. Kitcher, Philip (109)
29. Sober, Elliott (101)
32. Hawthorne, John (97)
40. Anderson, Elizabeth S. (83)
45. Korsgaard, Christine M. (80)
51. Priest, Graham (79)
53. Burge, Tyler (77)

"Generation X" or "Millennial" (born 1965 and later) [list extended to 14 due to a tie]

14. Chalmers, David J. (117)
45. Schaffer, Jonathan (80)
78. Sider, Theodore (68)
129. Godfrey-Smith, Peter (53)
138. Stanley, Jason (51)
156. Enoch, David (48)
156. Prinz, Jesse J. (48)
165. Weatherson, Brian (47)
173. Levy, Neil (46)
203. Craver, Carl F. (42)
203. Kriegel, Uriah (42)
203. List, Christian (42)
203. Nolan, Daniel (42)
203. Thomasson, Amie L. (42)

(In most cases, I have exact birth year from publicly available sources such as Wikipedia, but in some cases I estimate based on year of Bachelor's degree, PhD, or first publication. I welcome corrections.)

As discussed in a previous post, one striking thing about this list is its lack of gender and cultural/racial diversity (see also these articles on lack of diversity in philosophy). But another striking feature is the prominence of the Silent Generation. Analyzed another way: Among the 25 most-cited authors, 6 are Greatest, 14 are Silent, 4 are Boomers, and 1 is Gen X. Among the top 100 (104 with ties), it's Greatest 25, Silent 47, Boomer 27, and Gen X 3. (Note also that Greatest is by far the longest generation, 28 years, compared to the Silent’s 18, the Boomer’s 19, and Gen X’s 16; arguably this should be figured into a generational influence divisor.)

Citation Patterns Over Time

A natural first thought is that the 2020s might just be peak-citation time for the Silent Generation. Maybe the work of the Greatest Generation is starting to fall back into the mists of history, and maybe the Boomers and Gen Xers haven't yet had their full impact on philosophical discourse.

However, this appears not to be the explanation.

As an initial analysis, I looked at what years (1900 through forthcoming) are most commonly cited in the SEP. The results:

[click to enlarge and clarify]

As the graph shows, citation year peaks around 2011-2013. Members of the Silent Generation were in their late 60s to mid-80s in those years. Some of them were definitely still publishing, but age 65-85 is not most philosophers' peak productive period. Consider the top ten Silents, for example. Lewis, Williams, and Nozick were already deceased by 2011. The most influential work of the remaining seven was published in the late 1960s to early 1990s.

Now I do think that raw publication-year data are potentially somewhat misleading. Stanford Encyclopedia entries tend, I suspect, to disproportionately cite recent work (5-10 years old) that has gained some attention, even if that work has not (yet) been very impactful, so as to stay up to date. (2011-2013 was more than ten years ago, but the entries tend to get substantial updates only every 5-10 years.) A better measure might be longitudinal trends in citation rank. My methods haven't been exactly the same year to year, but close enough.

All but five of the 202 most-cited philosophers in 2010 are among the 376 most cited in 2024, and the greatest decline in citation rank has been among the Silent Generation. We can see this by subtracting the natural logarithms of the ranks. (I use a negative log basis, because a decline from rank 11 to 20 is much more significant than a decline from rank 191 to 200). For the Greatest generation the average change is -0.13, for Silent it's -0.19, for Boom it's -0.09, and for Generation X there's an average rank gain of +0.21. There's a similar pattern if we compare the 2014 and 2019 analyses with 2024: The Gen Xers are rising in relative rank while all other generations are declining.

These numbers exclude people who are new to the rankings (or who fall completely off the rankings), and most of my ranking updates contain some new authors from each generation -- partly because I expand the length of the list every year but also partly because some people gain in citation rate even well past their death.

One approach to that analytic problem is to compare authors ranked at least 300 (304 with ties) in 2024 with the 2019 list of 295 authors: approximately comparable lists, five years separated. Twenty-seven authors were among the 2019 top 295 but not the 2024 top 304: 6 Greatest, 10 Silent, 9 Boomer, and 2 Gen X. Conversely, thirty-six authors not on the list in 2019 were among the top 304 in 2024: 0 Greatest, 9 Silent, 12 Boomer, and 15 Gen X.

As one might expect from the various analyses so far, the Silents are even more disproportionately represented in the 2010 rankings than in the 2024 rankings: Among the top 25 in 2010, 16 were Silent, compared to 7 Greatest, 2 Boomer, and 1 Gen X.

The analyses thus all tell a similar story: The high representation of Silent Generation philosophers in my list of the most-cited Stanford Encyclopedia authors cannot be that it is currently their peak citation time.

Further indirect support for this claim also comes from an old finding of mine, drawing on Philosophers Index abstracts, that philosophers tend to have their work discussed most when they are approximately age 55-70.

The Not-So-Silent Generation and the Baby Boom Philosophy Bust

So, what explains the Silent Generation's disproportionate representation among the most influential philosophers in the mainstream Anglophone tradition? I suggest that their influence is due to their objective importance. They achieved this importance through lucky timing and rising to a cultural occasion.

In the Anglophone world, especially the United States, the 1960s and 1970s were times of sharp university enrollment growth, as Silent Generation scholars were hired to teach the Boomers, as the college degree came to be seen as the standard path to social status and economic security, and as universities basked in the high prestige of science in this era (cultural pride in the space race, the success of the Manhattan Project, the polio vaccine, computers, antibiotics....). The academic job market was ridiculously easy by the standards of every subsequent decade, and professors from this era tell tales of how they landed jobs in the most prestigious universities sometimes with a single phone call.

The Silent Generation thus had a great demographic advantage: They were entering the profession in boom times. They engaged with their elders (Quine, Rawls, and Strawson, for example; Putnam and Davidson are edge cases due to Putnam's near-cutoff age and Davidson's late start), but even more, they engaged directly with one another, filling the journals with articles about the issues that interested them. Much of their seminal work was published in the 1970s while they were relatively young, and this work framed the debates of the 1980s, and the 1990s, and the early 2000s, and to a substantial extent (as my SEP analyses suggest) even today.

The Boomers entered the academic job market mostly in the doldrums of 1980s, when there were far fewer open positions at elite universities. They grew in the shade of the Not-So-Silents, who were then mid-career and in no mood to yield the floor. Their work was largely shaped in reaction to leading Silents, such as Lewis, Kripke, Williams, Nagel, Searle, Van Fraassen, and Fodor. (I suspect this was especially so in the so-called "core" areas of philosophy of language, philosophy of mind, epistemology, and metaphysics, somewhat less so in ethics, political philosophy, philosophy of science, aesthetics, and history of philosophy.) There was just less of an opportunity for Boomers to shape the dialogue.

To some extent, a similar story holds for Generation X: The older Gen Xers (like myself) entered academia as the (Not-So-)Silents were senior professors in their sixties -- young enough to still be active, old enough to have the most senior positions in academia, in that sweet-spot between ages 55 and 70 when philosophers tend to receive the most prestige and attention. It is perhaps a little early to tell how badly shaded out the Gen X philosophers have been. Still, I'm inclined to think it's clear that we have been at least somewhat shaded out. We Gen Xers are now on average about age fifty, and so far probably only Chalmers has had the kind of impact on the field that the leading Greatest and Silent generation philosophers generally had by age fifty. (As noted above, in the 2024 SEP rankings, only three Gen Xers rank among the top 100: Chalmers at #14, Schaffer at #45, and Sider at #78.)

A Golden Age of Philosophical Naturalism?

All this said, I don't think demographics is the whole story. The Silents also had an occasion to rise to: the articulation of a thoroughly secular philosophical worldview. There have of course been atheists and scientific naturalists in every generation of philosophers in modern history, but in all previous historical contexts, these "naturalist" philosophers were to some extent on the defensive. The Silent generation was the first generation that took atheism and scientific materialism for granted. (Of course not everyone was a naturalist, but in mainstream Anglophone academic philosophy circles, critics of atheism and scientific materialism were very much on the defensive.) This created a context in which that generation could begin to explore in detail, and in dialogue with one another, in a supportive but also competitive context of shared secular assumptions, scientifically inspired approaches to the mind, language, meaning, and value. Arguably, it was a Golden Age of philosophical naturalism, laying the foundations on which all subsequent naturalist approaches have been built.

This is my theory, then, of the Not-So-Silent Generation in mainstream Anglophone philosophy. They had a huge demographic advantage in being hired just as university enrollments were booming, and a major philosophical task fell in their laps through cultural timing: the task laying the foundations of a thoroughly secular, scientific philosophy. They rose to this task and thus became not just a demographically dominant but a philosophically important generation, which will collectively be remembered (perhaps through a few emblematic names).

Is there a broad philosophical task of similar magnitude facing the now-rising generation of philosophers? I'm not sure. (As Hegel said, the owl of Minera flies only at dusk: We understand our cultural moment only in retrospect, as it is fading into history.) But maybe Artificial Intelligence and breakthroughs in the capacity to control human and non-human physiology will radically transform the world, enabling new types of life on the planet (conscious machines? post- or trans-humans?). If so, then maybe Millennial and Zoomer philosophers will have their own world-historical task to rise to: that of helping us understand the philosophical implications of the radical transformations such technologies enable.

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Related:

"Discussion Arcs" (Apr 27, 2010)

"At What Age Do Philosophers Do Their Most Influential Work?" (May 12, 2010)

"The Base Rate of Kant" (Jan 26, 2012)

"Age Effects on SEP Citation, Plus the Baby Boom Philosophy Bust and The Winnowing of Greats" (Sep 27, 2019)

"Where Have All The Fodors Gone? Or: The Golden Age of Philosophical Naturalism" (Nov 18, 2021)