Portrait of an ISTP:
Just as impulsive as other SPs, the ISTP's life is artful action and action is end in itself. Action for the ISTP is more gratifying if it is born of impulse rather than of purpose. If the action is in the service of an end or aim, let the aim look out for itself; it cannot be allowed to influence execution. The act is self-directed, self-leading, containing its own imperatives which cannot be suborned to mere rules, regulations, or laws. ISTPs are egalitarian and can be fiercely loyal to "brothers," but they can also be fiercely insubordinate, seeing hierarchy and authority as unnecessary and even superfluous. It is not so much a matter of going against regulations as it is simply ignoring them. The ISTP must do his or her thing, free to vary each next move. And ISTPs are, or want to be, proud of their ability to make the next move skillfully.
ISTPs are often fearless, risking themselves more than other types, despite (even frequent) injury. Of all the types, ISTPs are most likely to pit themselves, or their technique, against chance, odds, or fate. They thrive on excitement; they crave some excitement each day, in the form of fast motion racing, sky diving, or surfing, for instance. This hunger for action makes them more subject to boredom than any other type, their urge driving them to faster pace. Strangely, however, they are not bored while doing their thing, even though there may be long stretches when nothing happens, as during travel, surfing, hunting, or fishing.
The ISTP nature is most easily seen in their mastery of tools, tools of any kind, from microscopic drill to supersonic jet. From an early age, they are drawn to tools as to a magnet; they must manipulate them, and tools fall into their hands demanding use. Many pilots knew by the age of five that they were going to be pilots. ISTPs tend to take up activities that allow them to use tools: driving, steering, operating. And if a given tool, whether scalpel or earthmover, is operated with a precision that defies belief, that operator is likely an ISTP. Others use tools, of course, but not with the virtuosity of the ISTP. Indeed, we must call ISTP's the tool artisans, for they above all others command the tool and bend it to their impulse. But again, ISTPs personified in Michaelangelo and Leonardo work (or better, play) with their tools on personal impulse and not on schedule. If an externally imposed schedule coincides with impulse, fine; if not, so much the worse for the schedule.
One tool especially attractive to the ISTP is the weapon. Should ISTPs turn against society (for whatever reason), they wield their weapons with lethal genius to support their rejection. The hit man of today, the gunslinger of the American West, and the duelist of 18th Century Europe, may be seen as virtuosos of precision homicide. Hit man, gunslinger, and duelist alike took pride in their prowess. Fortunately they face their own kind in battle, the good warriors of the land: soldier, marshal, police, intelligence agent. This is not to say that all warriors, good or bad, are ISTPs, or that ISTPs are all weapons experts; rather that the weapon virtuoso is more frequently ISTP than not.
ISTPs also play on impulse, taking off at any time just because they "feel like it." (We are advised not to try to stop the ISTP who "feels like" doing something.) The neurosurgeon does crop dusting on the side and rides a motorcycle to the airport, and the financier goes on a hunting trip in the middle of an audit (i.e., SJ scrutiny). There can be no end to the ways ISTPs seek thrills in play. Although they may have the appearance of loners in their work, they nonetheless hang around their own kind in play. The climbers, racers, flyers, hunters, and in general, movers, flock together. The companionship is mediated through the tool, and conversation is sparse and terse.
Like the ISFPs, ISTPs communicate through action, and show little interest in developing verbal skills. Indeed, this lack of interest in communication may be mistaken for what well meaning but misguided medics and educators call "learning disability" or "dyslexia," both preposterous notions when meant as explanations. Let ISTPs get near a tool of any complexity and power and see how fast they pass up everybody in learning to use it and how precise their lexicon in talking of its features.
Despite their egalitarianism, insubordination, and love of freedom, they can be leaders, even great ones. But they must be "up front," sword in hand, leading the charge. That is to say, ISTPs can be very successful as battle leaders, for instance, no matter how large or small the force under their command. Their supreme realism, timing, and sense of expediency allows them to seize the moment and fully exploit whatever resources can be gotten (theirs or others) and capitalize on deficits and mistakes of their opponent. Theirs is an expediency or exploitative leadership, based on a special kind of intelligence which may be called artistic concreteness. Yes, for the ISTP battle leader, combat is an art, an intellectual game, not in the sense of strategy (that is for NTs), but rather using whatever is at hand to defeat the other with the least injury. Battle leaders are duelists. Patton was such a leader, and we must credit Marshall (an NTJ strategist) for seeing beneath that flamboyant, impulsive, insubordinate, and reckless exterior a peerless warrior. The same credit goes to Grant (another NTJ) for selecting Sheridan (STP), and to Hitler (ENFJ) for selecting Rommel (ISTP). Patton, Sheridan, and Rommel were cut from the same cloth and showed the same artistic espionage and rapier-like tactics.
Glory is a pre-20th Century concept better understood by the ISTP than by others. Or at least the ISTP is more interested in it than most others. In battle there is glory, for it is in battle that one can exercise one's lethal skills with positive sanction. The Seven Samurai were glorified and so have been duelists down through the ages. Foss, Boyington, Fonck, and von Richtoffen, all virtuosos of the winged machine gun, are still glorified heroes. But there are hundreds of warriors just like them in nature. One can test one's mettle in lethal duel, there's glory in it, as the film The Great Woldo Pepper showed most poetically.
The education and intelligence of the ISTP is worth special comment. Possessed of artisan intelligence, ISTP is not in the least interested in the clerical, interpretive, and "science" curricula that abound in the 20th Century school. The other SPs, equally bored by the school, will at least act as if they're trying to learn, but not ISTP. ISTP will stare coldly into the eyes of the teacher and not even say no. No amount of cajoling, bribing, rewarding, punishing, or threat will get them to do their school work. School work, quite apart from being irrelevant to the talents of SPs, is, after all, mere preparation for something the ISTPs figure they're never going to do anyway. SPs do not wish to prepare for anything and ISTPs are careful to make this clear to their would-be instructors. What is there to do, now, that is worthwhile? ISTP will not sit still (literally) for the trivial fare dished out (sanctimoniously, in the eyes of the ISTP). Most seem to agree that ISTPs "should" do their school work. But why? The arguments are piddling and incoherent, warranting the scorn they get from the unshakable ISTP. ISTPs are not "minimally brain damaged," or "hyperactive," or "dyslexic"; they ore active, and they are stubbornly insistent upon getting to do, in school, some things that allow them to test their intelligence and their mettle. Name-calling and pill-pushing won't change them, other than destroying their self confidence and perhaps creating a stimulant addict now and then. Give them a tool-centered curriculum and watch their speed.
Behaviorally the ISTP is more like the ESTP than any other type, and the older they get, the greater the resemblance. When young, ISTPs may look very much like ISFPs, but as their confidence and pride increase this resemblance recedes. Jungians think ISTPs are just like INTPs with only minor differences, but this is based on the definition of ISTPs as "introverted thinking types." INTPs are logicians, philologists, and architects in the way they think, but ISTPs are completely disinterested in these pursuits. Even a cursory observation of a few clear-cut ISTPs will show how striking the contrast, and how trivial the resemblance.
Still, the most important thing about the ISTPs is their communality
with the other SPs. We might think that there would be some resemblance
to the ISTJ, having as they do, "IST" in common. But no, their behavior
is antithetical in almost every dimension of comparison. One is pessimistic
while the other optimistic; one is parental, the other, fraternal; one
saves, the other spends; one believes in rules, the other is instinctually
insubordinate and recalcitrant to rules; and so on. ISTPs have infinitely
more in common with the very different ESFP than they do with any NT or
SJ; besides the above, their mood is one of good cheer, they are loyal
to their equals, they want no obligations, duties, or confining promises,
are uncomplicated in their desires, and are trusting, receptive, and generous.