Father Time Is Undefeated

Intelligence, and How a Judge Advocate Can Prepare for Its Inevitable Decline

By MAJ Jonathan M. Harrar

Article published on: May 29, 2026 in the 2026 Issue #1 of Army Lawyer

Read Time: < 30 mins

Landscape with Father Time and Personification of Craft and Labor. Cripijn van de Passe, Cologne 1589-1611. (Source: Rijks Museum)

Father Time remains undefeated. So it’s not him you should be angling to beat. It’s that gnawing cry for purpose that will eat straight through you if you let it.1

The human mind, like the body, experiences deleterious effects while aging.2As individuals mature, they will have an inevitable decline in certain cognitive abilities tethered to their intelligence.3While harsh, denying this inevitability will lead to frustration, anger, and lack of satisfaction, while eating away at one’s sense of purpose.4Yet that decline does not necessarily signal the end of a successful and fulfilling career. Thankfully, intelligence is multifaceted. To thrive in the latter half of one’s professional career, it will be crucial to focus on leveraging crystallized intelligence.5This article explores the concepts of fluid and crystallized intelligence, discusses the research establishing that an inevitable decline is coming, and analyzes the potential implications of these topics for a military legal career. Ultimately, this article also offers some practical recommendations to prepare for the back half of one’s professional legal career.

First, a “Brief” Discussion on Intelligence

The formal study of intelligence (sometimes referred to as cognitive science) dates back to the late 1800s.6In the early part of the twentieth century, debates about how to accurately measure intelligence sans cultural or subjective bias gained popularity.7Initially the “measuring scale of intelligence” was comprised of a series of thirty brief cognitive tests intended mostly for school-aged children.8This “measuring scale of intelligence” was utilized from 1905 through the 1930s via the Wechsler-Bellevue intelligence test, which was well-suited to measuring intelligence in adults and included both verbal and performance measurements without memorization.9Without memorization, the test could not be “gamed,” so it was a more accurate measurement of natural abilities.10

Unsurprisingly, the U.S. Army had a vested interest in testing potential recruits and their natural intelligence.11After a few more years, researchers still criticized the IQ tests as relying too much on acquired skills rather than intelligence per se.12They believed the forty-four different types of intelligence tests available at the time still focused too heavily on verbal material, had cultural biases, and suffered from poor reliability.13Researchers wanted tests that were “culture-free” and were designed with non-verbal instructions and instead simply utilized “work it out” examples.14It was amidst this backdrop that theories on how intelligence actually worked and could be quantified gained popularity.

Initially, some researchers considered intelligence to be a measurement of one’s verbal, spatial, numerical, and mechanical skills quantified as their “g-factor” (general intelligence).15Others posited that intelligence boiled down to one’s combination of analytical, creative, and practical intelligence.16Still others tried to capture all of the “primary mental abilities” beneath the umbrella term of “intelligence” by simply listing the skills that included verbal comprehension, verbal fluency, number facility, spatial visualization, perceptual speed, memory, and inductive reasoning.17Later, Howard Gardner compiled his own list dubbed the “multiple intelligences” comprised as linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, and intrapersonal, and naturalist intelligence.18More recently, emotional intelligence has also been added to the intelligence lexicon and adds further layers to the discussion.19As with most scientific endeavors, disagreement and debate arose.

While the literature failed to deftly define intelligence or how to objectively test for the same, Raymond Cattell offered a now widely accepted theory of intelligence that synthesized the previous works. He theorized that intelligence tends to come in two classes or dimensions: fluid and crystallized.20During Cattell’s critique of culturally biased intelligence tests, he first proposed the distinction between fluid and crystallized intelligence.21He opined that “fluid ability has the character of a purely general ability to discriminate and perceive relations between any fundaments, new or old. It increases until adolescence and then slowly declines.”22

Furthermore, fluid intelligence captures the ability to reason, think flexibly, and solve novel problems in a novel way.23It allows humans to perceive and draw inferences about relationships among variables to conceptualize abstract information, which ultimately aids in solving a problem.24If you have ever had the pleasure of undertaking a test filled with ostensibly unrelated patterns, photos, or picture sets, you are endeavoring in a fluid intelligence exercise. Without rules and without context, the test determines if you can choose the correct answer without help, context clues, or experience. While these may appear as simple childhood games, the same fluid intelligence skills apply in life. Confronted with a new job, new human relationships, new software, and new acronyms (of which the Army has many), those with higher fluid intelligence figure it out faster.

Conversely, crystallized intelligence represents a person’s knowledge gained via learning and experiences.25The SAT26and Law School Admission Test (LSAT) can be “gamed” with tutoring, courses, practice, and time—exactly what the fluid intelligence tests were attempting to isolate away from.27Importantly, while fluid intelligence diminishes with age, crystallized intelligence relies on accumulated knowledge and skills and can be utilized to great effect.28Knowing the rules can be quite the advantage to a lawyer, and utilizing them to great effect separates the novice from the expert. Cattell also described “[c]rystallized intelligence as the ability consist[ing] of discriminatory habits long established in a particular field, originally through the operation of fluid ability, but no longer requiring insightful perception for their successful operation.”29As one grows older, the accumulation of knowledge increases crystallized intelligence.30In Cattell’s theory, fluid and crystallized intelligence interplay with one another as we age; while fluid intelligence drops off, crystallized intelligence can continue to grow.31

More on Fluid Intelligence

Fluid intelligence is not easy to quantify. This begs the question: what exactly are we losing as we age? What is clear is that fluid intelligence includes the ability to reason, think flexibly, and solve novel problems.32It is much higher in one’s early adulthood and diminishes steadily in one’s thirties and forties.33Fluid intelligence also refers to “reasoning and novel problem-solving ability.”34Some more examples of fluid intelligence are solving puzzles, constructing strategies or processes to deal with a novel problem, seeing ostensibly unrelated patterns in data, and speculative philosophical reasoning.35

Fluid intelligence can also be directed to any problem—math, science, law, music, language, etc.36It “appears to operate whenever the sheer perception of complex relations is involved. It thus shows up in tests where borrowing from stored, crystallized, judgmental skills bring no advantage.”37Obviously, it does not function in a vacuum. Complicated problems will necessarily utilize crystallized intelligence too, but you simply have less of a knowledge base at a younger age.

The endeavor of law school may serve as an example of the marriage of crystallized and fluid intelligence to illustrate both. Most students matriculate in with above-average reading comprehension skills, writing skills, and a base of study practices, discipline, and habits from which to approach the study of the law (i.e., crystallized intelligence). However, the 1L year introduces novel concepts like intent, causation, counterintuitive property concepts, common law case law, how it all meshes with model statutes, and, of course, legal writing.38Fluid intelligence is working overtime during that 1L year.

Now, imagine going to law school in your forties or fifties with all other variables remaining the same. Would you advise the student who has lost some of their fluid intelligence to approach it the same way? Of course not. Recognizing that there is a difference is crucial for both students to succeed. The reality is that the student whose fluid intelligence has begun to dip should approach the problem differently.39Approaching it the same way, despite the disparate abilities, would be foolhardy. This thought experiment should reveal Cattell’s theory—humans lose their fluid intelligence as they age and rely more heavily on crystallized, contextualized knowledge.40

Unfortunately, some researchers suggest fluid intelligence may diminish even earlier. “Fluid intelligence has long been thought to peak during the late twenties before beginning to decline gradually.”41As you age, there are structural changes in the brain that likely explain this spiral.42Theories about why differ greatly, with some attributing it to decreased blood flow, cellular changes, or atrophy as a result of more reliance on crystallized intelligence.43Not only is the prefrontal cortex the last part of your brain to develop after childhood, it is the first to decline in adulthood.44

While the academic literature is dense, some anecdotes may also be persuasive. Charles Darwin was in his mid-twenties when he developed the ideas of natural selection and evolution, though he waited until he was older to publish his findings.45Albert Einstein, the paradigmatic genius, was just twenty-six when he proposed his ground-breaking special theory of relativity.46Some of the current largest companies in the world were started by young adults. Mark Zuckerberg started Facebook at nineteen years old,47Bill Gates began Microsoft at twenty years old,48and Steve Jobs co-founded Apple at just twenty-one.49Even the United States’ founders were relatively young when they suggested the bold (and novel) idea that the people, not the government or a monarch, should manage themselves. Thomas Jefferson was thirty-three, James Madison was twenty-five, and Alexander Hamilton was just nineteen years old.50George Washington was downright geriatric at forty-four years old in 1776.51However, with age comes wisdom, experience, context, and saliently crystallized intelligence.

More on Crystallized Intelligence

Crystallized intelligence, the ability to apply previously obtained information, increases as we age.52This is intuitive because the older we are, the more prior education, experience, knowledge, and skills can be obtained. While “[f]luid intelligence is conceptualized as the decontextualized ability to solve abstract problems . . . crystallized intelligence represents a person’s knowledge gained during life by acculturation and learning.”53Mercifully, crystallized intelligence builds and compounds.54

Learning a language is a great example of obtaining crystallized knowledge we take for granted as adults. It starts with learning letters, the sounds of those letters, how those letters go together to form individual words, then simple sentences, complex paragraphs, stories, books, and so on. Fluid intelligence may help initially in appreciating the abstract nature of what the letters represent, but eventually, the crystallized intelligence takes over until the words themselves introduce and implicate novel concepts that fluid intelligence addresses. Relevantly, crystallized intelligence tends to rise gradually and stably throughout adulthood and does not begin to decline until one’s sixties.55Said another way, crystallized intelligence provides context. A seasoned prosecutor knows what a case is worth; a contracts attorney can pull from their rolodex of previous disputes to resolve a “new” problem; and a leader can rely on prior experiences and myriad relationships with others to address personnel concerns.

A “seasoned” attorney, judge advocate (JA), and leader knows the rules better, which is why the accumulation of crystallized intelligence creates the oft sought-after wisdom.

Like with fluid intelligence, many examples exist of those who have thrived utilizing their crystallized intelligence in the latter half of their career. The professorial archetype is the grey-haired, older, wiser person who has likely forgotten more information than their students currently know. Their proverbial rolodex of information is exponentially larger by sheer volume. Many professions take advantage of those with vast crystallized intelligence stores, such as professors. The average age of current Supreme Court Justices, for example, is sixty-five years old.56Historians necessarily utilize crystallized intelligence to digest and contextualize troves of information. The author David McCullough wrote his Pulitzer Prize-winning biography on John Adams when he was sixty-eight years old.57He continued to write, publish, and teach until his death at eighty-nine.58Philosophers too, sometimes defer their final theories until later in life. Immanuel Kant published his Critique of Reason when he was fifty-seven years old.59Unlike the fluid intelligence breakthroughs of the youth leaders, historians and deep thinkers successfully navigate their professional lives well into their elder years using their gained wisdom.

Wisdom is the zenith of crystallized intelligence. One group of researchers noted that as a “psychological trait, wisdom refers to a global psychological quality that engages intellectual ability, prior knowledge, and experience in a way that integrates virtue and wit, and is acquired through life experience and continued practice.”60Wisdom seems to marry the best of fluid and crystallized intelligence.

For JAs, the combination of experience, judgment, and troves of information is certainly a large factor in their success, as fluid intelligence sans experience would not create sage advice/guidance. As JAs age, however, they must think about when to shift toward more focus or reliance on crystallized intelligence so as to not get left in a fluid intelligence-based mindset or role and lag behind the abilities of their younger selves.

From Strength to Strength

Arthur Brooks discussed this exact predicament in his book From Strength to Strength: Finding Success, Happiness, and Deep Purpose in the Second Half of Life.61Brooks briefly synthesizes the above research concerning

fluid and crystallized intelligence and offers that riding “the wave” of crystallized intelligence following the diminishing fluid intelligence wave will prove far more beneficial than attempting to accomplish the same feats later in life with diminished capacities.62Moreover, he suggests the latter will no doubt lead to frustration, bitterness, bad health, stress, and generally negative outcomes.63Instead, if a hard-charging, striving, dedicated, and driven professional were able to recognize the inevitability of the dip in the fluid intelligence curve and “jump” onto the still-increasing crystallized intelligence curve, their potential remains limitless.64

Given that one’s fluid intelligence dips at some point in their life/career, reliance only on the same in the latter half of one’s professional career would be unwise.65Yet the crystallized intelligence curve is still progressing steadily upwards and only begins to dip much later in life.66Recognizing this reality, preparing for this eventuality, and taking the jump from reliance on fluid intelligence to crystallized intelligence will be critical not only to objective success but also to subjective happiness. This is not a blind leap of faith; rather, it is a conclusion grounded in Cattell’s research and findings.

Brooks argues that relying less on innovation and more on instruction will play more to one’s crystallized strengths.67Brooks bolsters his argument to jump the curve by quoting the ancient Roman philosopher Cicero, who wrote to his son that as we age, we should (1) be dedicated to service; (2) use wisdom to enrich others; and (3) counsel, mentor, advise, and teach.68The existence of the second curve should be welcome news. Even after certain skill sets that may have propelled one to success diminish, the same individual can attain even higher heights by jumping to the second curve/wave.69

Brooks warns that fighting against this reality will bring pain.70He suggests most successful people do not know that fluid intelligence declines and even more do not realize that crystallized intelligence can still grow.71Brooks acknowledges that it can also be unnerving to deviate from what one has always done that led to their success. Fret not, Brooks would say. By shifting to different strengths, the back half of one’s career can be as fulfilling and rewarding as the first. If the latter stages of one’s career are devoted to serving others with hard-fought wisdom, the transition will be far less perilous.72

These career decision points present themselves often for all JAs, but most notably for those at the field grade ranks. There are options to teach, supervise, become subject matter experts, or deviate entirely from previous professional experiences. Appellate litigation, contract disputes, ethics, and policy advising are all jobs generally reserved for more senior-ranking officers. Of course, there is always the option to stay the course and double down on previously obtained skills. A prosecutor or defense attorney who has practiced criminal justice their entire career can now continue specializing with the advent of the Office of the Special Trial Counsel and complex litigators. Even among those specializations, Arthur Brooks would likely recommend that practitioners begin to rely more heavily on a new strength.

Army Doctrine and JAG Corps Policy Seem to Agree

Greg Maddux, one of the greatest pitchers of all time, threw a baseball 95 mph when he was drafted in 1984.73To anyone who followed his career, this may come as a surprise. When he retired at forty-three years old after twenty-three seasons, he threw absolute junk.74He was known more at that point for his command, off-speed pitches, and baseball IQ than speed.75That fastball pitcher adapted to the reality that he could not throw heat forever, and he adapted his game despite the massive change. JAs, like MLB players, are “drafted” at a young age. The skills that made them excellent accession candidates may not be the same ones that make them great field-grade officers in the Judge Advocate General’s (JAG) Corps. Like Maddux, they need to learn to throw different pitches.

Along the fastest track, a JA obtains their undergraduate degree at twenty-two years old, finishes law school roughly three years later at twenty-five, commissions into the Army shortly thereafter, and pins on their major rank rarely younger than thirty-three years old.76Thus, even the youngest JAG Corps majors are well on their way to needing to embrace the crystallized intelligence curve. In sports parlance, they need to learn to throw different pitches. Or, as Brooks aptly described it, they need to shift from one strength to another strength. By either coincidence or design, the Army and JAG Corps seem to recognize this need to change strengths.

Field grade officers are often urged to shift away from their past successes as action officers and “doers” and instead focus more on leadership.77Leadership, by doctrine, mostly concerns relationships with people.78This doctrinal focus on relationships nests well with Cicero’s advice to teach, coach, and mentor. Understandably, this may send humbling chills through any JA who has spent the bulk of their career primarily performing legal work. Telling someone who has spent their entire professional career brute-forcing knowledge into their brain, achieving results, and outputting at extremely high levels to now pivot to different strengths and skillsets is a large ask. To many, this may prove difficult. They may have achieved promotion and relative success through reliance primarily on their creativity, fluid intelligence, and innate raw smarts. While some may hope that will continue to work as they rank up, it may not, according to Cattell and Brooks.79But thankfully, there is a second curve.

Leadership is not just about having authority; it is about supporting and influencing others to achieve a common goal.80Army Doctrine Publication 6-22, Army Leadership and the Profession, outlines three types of leadership: direct (individuals and small groups), organizational (organizations), and strategic (overall direction and development), with different responsibilities of each.81To be effective, an officer must be able to operate effectively at each level, even at the same time. While these leadership skills may have only been nominally used as an action officer, particularly for JAs, the wisdom, experience, and ever-growing crystallized intelligence gained during that time means that senior JAs entering new roles may have more to offer immediately coming into positions than they might think. JAG Corps policy certainly agrees.

The current JA career model states that during a JA’s first years, they are meant to develop as an officer, gain competence across legal functions, identify legal interests and aptitudes, and eventually “develop leadership baseline skills.”82As their careers progress, JAs are expected to increase their legal expertise, lead and develop their teams, manage offices, and eventually advise Army senior leaders.83In addition, the JAG Corps recently modified its internal personnel policies to allow senior leaders to specialize in a legal functional area.84The new JA career model now allows for senior JAs to act as “specialists in a legal functional area, serve as command counsel, or both.”85Previously, the Corps focused on training JAs to be broadly skilled lawyers, having some level of knowledge in various fields, but rarely were they specialists per se.86Prior iterations of internal policies required JAs to “combine the versatility to practice in every legal function . . . [as] versatility will remain essential throughout a [JA’s] career” and that all JAs “must be competent to practice in any area.”87

The ability to now specialize is a big change, and it potentially makes heeding Brooks’s warning to shift to a different strength feel less intuitive. Nonetheless, doing so is critical for success. Greg Maddux was wise; he pivoted to throwing junk after his fastball slowed and, in doing so, he continued to have success. JAs in the back half of their careers should similarly look for different pitches to throw (though not necessarily “junk”).

Considerations for Your Consideration

Ignore the Science at Your Own Peril

Raging against reality is dangerous, especially for lawyers, who already face the unique stressors that inherently come with a legal career.88Older JAs should not ignore the science by simply bearing down, throwing more hours at tasks, or undermining their own success with too much hubris. It would be downright Sisyphean to expect the same outputs as one’s younger self utilizing the same manner and methods, and, as Brooks notes, attempting to do so in this case will just cause frustration, bitterness, bad health, and stress.89

A senior JA is “rapidly” losing their fluid intelligence.90Maybe that mental degradation is already happening, or maybe it remains deferred; but be assured it is coming for everyone. Obviously, humans and their talents and intelligence exist on a spectrum, but overall, it would be prudent to at least prepare for this eventuality. Like Pascal’s wager,91the worst-case scenario would be that you obtained new skills that you can layer on top of your fluid intelligence. Nothing is lost, but much could be gained.

Thankfully, lawyers in the JAG Corps can rely on crystallized intelligence to be extremely successful in either leadership roles or performing as specialists leading teams of legal professionals. A profession that requires crystallized intelligence might have its practitioners peak later but thrive longer. What are lawyers if not moonlighting historians? A direct- or cross-examination is not very different from simply teaching a jury or judge about something that already happened. JAs, particularly aging ones, are able to absorb new information and place it into its historical context. New statutes, regulations, case law, and, of course, practical lived experiences inform their judgment and learned counsel. Those with experience paired with a catalog of relevant and useful information come closest to being wise. An experienced lawyer’s judgment is their currency. Do not fret about the oncoming reality; embrace it.

Coach from the Sideline, Not the Field

Few things are sadder than watching a formally formidable superstar athlete attempt to play their sport too long. They step onto the field, court, ice, or ring a mere shell of their former self.92Muhammad Ali fought well past his prime and suffered the debilitating effects as a result.93Michael Jordan, the greatest basketball player the world has ever seen,94held on admirably in the last two years of his career with the Washington Wizards but could not affect the game like he once could.95At best, it is awkward; at worst, it is dangerous. They could have been working toward becoming coaches, business owners, team consultants, part of their respective alumni programs, or transition into broadcasting, but instead, they held on too long. The opportunity cost of insisting on staying in the game is unknowable but self-inflicted. Additionally, the cost to that player aside, they also took up a slot on the team. It was arguably a bit selfish, a bit self-centered, and short-sighted. Following Brooks’s advice, one might suggest: Don’t be like Mike.96

Senior JAs should rely on the vibrancy of their more junior, creative, fluid thinkers for the minutia, brute forcing, and fluid intelligence-based skills. They are the backbone of the law firm’s work product. Senior leaders are editors, synthesizers, and context creators. They are the teachers, the mentors, the literal coaches of the more junior attorneys in the firm. These skills are invaluable and not to be shortchanged. Waiting too long to transition to the next phase of one’s career could undermine the mission and come at opportunity costs to the organization.

For example, AI is changing legal research, the presentation and review of evidence, how legal briefs are written and edited, and it is revolutionizing how legal documents are drafted.97It is changing everything. Perhaps the junior JA, rich in fluid intelligence, is the best suited to identify best practices in applying AI to our respective fields of practice. Cattell’s theory may explain why, as the novel problem-solvers are the new employees who are far more adept at adapting than the more senior lawyers.98Senior JAs knowing themselves, their people, and the strengths and weaknesses of both will be immensely important in focusing the efforts of any legal team. Trusting subordinates to embrace new technologies, new law, and doing the raw work is critical. After all, it empowers them, and they are still rising on the fluid intelligence curve, but they need their leaders’ guidance and crystallized intelligence. As Cicero said, teach. Senior JAs should devote the back end of their professional career to serving others with their hard-fought wisdom. They will only excel with them, not in spite of them or instead of them.99

Greg Maddux. (Source: George Bush Presidential Library)

Jump the Curve!

Even within the Corps’s shift toward allowing JAs to specialize in an area of law, the reality is that focusing on leading, teaching, mentoring, and utilizing one’s crystallized intelligence more than fluid intelligence later in a JA’s career offers the widest path to success. With increased rank comes increased responsibility for people, macro-level missions, and the health of the organization as a whole. We become stewards of the practice and profession, and none of us, even the specialists, operate in a vacuum, despite how much one may try. JAs, like any officers in the Army, function within a larger ecosystem that is, in many respects, self-managing.

Even the specialists lead, so JAs should not and cannot allow themselves to think that they are not a leader or that their areas of law are so niche that they need not broaden their skill sets.100This article simply suggests treading carefully in deciding how to approach your chosen career path. Heed Cicero’s letter to his son that teaching, coaching, and mentoring are not quitting. Instead, it is shifting from one strength to the next and, in the long run, can benefit you and the organization equally.

Conclusion

JAs are not getting dumber as they age. Such a suggestion is not the thesis of this article. They are, however, relying more and more on their life experience, education, and crystallized knowledge as their careers progress. Thankfully, lawyers are not professional athletes (at least, not most of us101). Father Time’s clock need not run out as quickly as it might for a physical profession. While knees, backs, and shoulders give out for professional athletes, JAs can utilize their brains far beyond the joints of their bodies. However, like an athlete who loses a step on the basketball court or football field, JAs need to adjust their game and eventually turn more heavily toward coaching instead of playing to extend their professional career. Focus on embracing a different strength, one that builds off your previous strengths, instead of fighting against Father Time. Embrace this reality, prepare for it, and ride the crystallized intelligence wave as long as you can. That will provide a purpose Father Time cannot take away . . . at least not yet. TAL

Notes