Your argument is as follows.
One who engages in the study of economics or social conventions (e.g, how people should live or how they'd find their ends meet) is an S.
Marx was concerned with such matters therefore he is an S.
Here is another rendition of your argument.
Anyone who is concerned with the study of the empirical world is an S.
Locke was an empiricist, therefore he was an S.
Why would somebody make such an argument? On a superficial level it seems to be the case that social conventions and economics are practical in their nature, more so than theoretical. Hence, they would appeal to an S mindset. It also seems to be the case that empiricism as an epistemology is more concerned with what could be observed around us, more so than with what can be theorized about. Therefore it also appeals to an S mindset more than the Intuitive.
The problem with such an argument is that Marx was not concerned with merely the practical aspects of economics and social affairs, he was concerned in theorizing about them. Locke was not merely concerned with observing the world with his five senses, he was more interested in ideas that surround the observable world. None of the above mindsets are indicative of a Sensing preferrence.
Suppose, there was a philosopher who was chiefly concerned with the social or economical affairs who was not much interested in theorizing about them. Would this prove that he was an S? Certainly not, but this would indeed suggest that he may have a Sensing preferrence.
Why does this not prove that such a person is in fact a sensor? Because sensing is an unconscious disposition towards engaging one of our five senses or more as opposed to engaging our imagination. What we will have observed in the case cited in the paragraph above is merely an instance of somebody engaging the faculty of Sensation. This does not show that such a person has a solidified unconscious disposition to use Sensation more than Intuition.
To find out if such a person has a solidified unconscious disposition to use Sensation more than Intuition it is necessary to conduct a thorough inquiry into his or her habits of mind. Studying their works alone does not enable us to accomplish this. That is the case because when an individual publishes his ideas, he is not in the position to behave in a way that he is prompted to by his natural dispositions. For example, a philosopher who is a Sensor would have a natural disposition to merely observe his environment without applying his imagination to his observations. Obviously, this habit of mind is undesirable in scholarly works and he would be forced to supress it. He would be unlikely to supress it entirely, hence his temperament would manifest in subtle, unclear ways.
Hence, to get confirmation that he is a sensor we would need to examine other instances of his life which allow for us to observe him when he is allowed to behave freely in accordance to his natural dispositions. Thus, if we wish to find Sensing philosophers, studying their writings is not enough, we must study their biography in order to find instances of their lives where their tendency to engage the Sensing faculty is less supressed.
Karl Marx's type was an INTP.
Reasons: At a point when he had the liberty to live in a way that he could choose to, he operated in a manner akin to that of a Bohemian intellectual, similar to the kind of a lifestyle an INTP would choose if he had an opportunity to. He slept at random times, was unaware of the spies in his house. (So Paul Strathern reports). (This is indicative of a lack of Extroverted Judgment of the INTP, most particularly Extroverted Thinking. This is the well known element of aloofness of this type which tends to be much less distinctly expressed in other types.) He maintained almost no contact with others, excluding Engels and those who have lived in his house. Clearly had a low social need. (This is indicative of the INTP's neglect of the Feeling faculties and the Extroverted faculties. No other type tends to neglect them more than the INTP.)
His ideas, although ostensibly relevant to the practical concerns of the people, as he wrote about poverty and political dilemmas that underpin social problems, were highly theoretical. Unlike an intellectual with practical concerns, he was not interested in directly influencing the environment of his time. He was merely interested in theorizing about it. He has not even dreamed of his works having a direct and immediate impact on his current society, as they were obviously much too complex to be easily understood and implemented. In fact, his works had not influenced society at all until 70 years after his death. This is indicative of the INTP's tendency to theorize without a clear cut goal to implement ideas.
Karl Marx's works were also systematic in nature. He argued that what he has accomplished is similar to what Charles Darwin has accomplished in biology, in fact he even wished to dedicate Das Kapital to Darwin for this reason. What Marx thought he has accomplished is a systematic overview of economical and political issues. Or simply has discovered the laws of economical and political occurences. This echoes the work of George Boole, a manifest INTP, who has published the Laws of Thought less than 20 years before the publication of Das Kapital.
The dominant faculty of the INTP is Introverted Thinking. This inclines them to gravitate towards highly systematic or logical thought. Other INTPs such as Descartes, Darwin (controversially, he may have been an INTJ), Boole, and Spinoza were most famous for their method.
Thus, here we have observed instances of Karl Marx having opportunities to live the way he wanted to, or to be true to his natural dispositions, and he has revealed a mindset most akin to that of an INTP. If he was an ESTP, there would have been no reason at all for him to live the life of a Bohemian intellectual, or to make no effort to acquire acquaintances. Moreover, if as an ESTP he wished to write about economics or political affairs, he would have no reason at all to engage in highly systematic and theoretical thought that INTPs tend to favor. Unlike Marx, he would not have engaged in seemingly endless chains of reasoning to prove his point in an attempt to discover some 'abstract laws of economics and politics'. Instead, he would be writing to the common people in a simple and a down to earth manner, as the intellectual disposition of the ESTP is such. Certainly the ESTP can behave in a manner akin to that of an INTP, or he could rely on Introverted Thinking and Intuition first and foremost, yet he simply would have no reason to do so unless he was forced. Marx was not forced. He wrote in such a manner on his own volition.
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John Locke was an INTJ. He also had an opportunity to write and behave in a way that was most natural to him. He was a systematic thinker, yet not nearly to the extent that the aforementioned INTPs were. He seemed to be more concerned with insight or acquisition of new ideas than with structuring his thought in a consistent and a rigorous manner.
Locke also lacked the element of general aloofness and lack of structure in his affairs with the external world. He did not live a life of a Bohemian intellectual. He was very impatient with those who seemed to be wasting time, even if it was their own. For example, at one point he has observed a group of men sitting next to him playing cards and engaging in non-sensical chatter. He sat down next to them and began writing down everything he could hear. Later it became evidence that his behavior was purposefully caustic.
In the introduction to his most famous work, you will find many essays that he regarded as the 'Epistles to the reader'. Which shows that unlike the aforementioned INTPs he was not merely concerned with working out his ideas with clarity and rigor, but he also made it a point to communicate with the reader in a way the reader could appreciate. This is evidence of externally focused judgment which appears to be missing in the natural dispositions of the INTPs.
His work on Political Philosophy, the the two Treatises of the Government were written in a much more accessible manner than Marx's Das Kapital. Primarily because they were relevant to the practical concerns of his time. Unlike Marx, Locke did not merely theorize about Politics, he made it a point to ensure that his ideas are relevant to the current state of affairs.
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David Hume was an ENTP. He wilfully maintained many acquaintances throughout his life. Unlike an INTP, he was very image conscious and his approach to his work evinced this. Hume was an exquisite stylist and aspired to make his writing as appealing to the reader as possible.
“It is well known that in his later life Hume time after time suppressed his most radical ideas in order to be better appreciated by the public, and it is characteristic that in his autobiography he describes the “ruling passion” of his life not as Spinoza would have done, as the urge of philosophical cognition, but love of literary fame. And this literary ambition was not of the nature which was content with immortality usually accorded to great thinkers by late posterity; but, practical and concrete as he was, he craved first and foremost the admiration of his contemporaries…And therefore he was consistently led to regard the judgment of the public as his supreme court, his only guide in his literary work.”
I am not prepared to assert that the quotation above is true, though it suggests what is true, or that he was naturally image conscious and this has reflected in his prose. Intellectual history has not documented a single history of an individual whose biography clearly evinces that such an individual was an INTP, yet is also naturally image conscious as Hume was.
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Jean-Jacques Rousseau was an eminent thinker with a dominant prevalent Sensing faculty. This manifests in his introspective thought, most notable in his autobiography the Reveries of a Solitary Walker. It is clearly noted that when he describes his inner world, his first thoughts are aimed not at abstractions but at his immediate physical environment and the particular sensations he experiences as a result. One may argue that Roussaue was a sensor because he believed that a savage life is noble and we must become more attuned with our instincts, however this view is illegitimate. It is illegitimate because a philosopher who is intuitive may have arrived at such a view for extra-typological reasons. Or simply because he thought that such a view is true. In that case the expression of his views would not be indicative of his natural dispositions or his temperament, as in that case he did not have the liberty to behave in a manner that was most natural to him. If he had such a liberty he would have followed his hunches which led him to believe that imagination is superior to sensation. However, if such a philosopher is intellectual honest, he would not espouse such views simply because his hunches lead him to believe that they are true. This leads me to reiterate my aforementioned criticism of how you have typed Marx and Locke. It is a mistake to believe that one's philosophical views are indicative of their temperament. Locke may have well been an empiricist because he thought that this position was true, and not because it is an expression of his typological mindset.
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"As Foxy Sarah once pointed out before her departure, many people on this board make illogical inferences as to the abilities of senors: being a sensor does not mean one is incapable of intuition. Preference does not necessarily predict prevalence.This thread is a prime example of the inherent bias on this message board population and their biased perceptions toward the past and consequently themselves. An education-rich childhood can easily bring the intuitive world (as well as develop "thinking" processes) that would otherwise go unfostered in many young. As such, I think there is a SEVERE bias in the assesments of types in the philosophy and scientific realms. Normally this would be ok, but I argue that an improper consideration of typology could lead students of philosophers towards illogical inferences about their works."
What could be said about this? It is true that students of typology tend to think that most, if not all philosophers are Intuitors. Such thinking, almost indubitably, is a result of their conviction that philosophical work requires for us to exercise our Intuitive faculties more than our Sensing faculties. Whilst this is true, it does not follow that all philosophers are Intuitors. Some Intuitors are capable of excelling at Sensing oriented activities such as sports, as today we can document many instances of athletes who are Intuitive by temperament. Similarly, philosophers of a Sensing temperament likely exist and have existed in the past. Being a certain type merely means that one's natural dispositions towards one kind of cognitive activity are stronger than one's dispositions towards another kind of cognitive activity. Nothing is stopping one from cultivating the cognitive faculties that one is not naturally attuned with. He may even cultivate them to such a degree that his skills with such faculties will be superior to the skills of the individual who is more naturally attuned with them.
I do not doubt that students of typology have a bias with regard to typing philosophers, yet the thread you have cited does not serve as an example. What you have pointed out is that people tend to think that most philosophers are Intuitive. In order to point out that they think so for illegitimate reasons, or as a result of their bias, you must cite an instance where they claim that a philosopher who obviously was a Sensing type as an Intuitive one. You have not done your homework.