A recent posting made over at The Splintered Mind makes great hay out of the view that Kant makes a number of "bad arguments" by which is meant that he defends or attacks a number of things, particularly in The Metaphysics of Morals that would not, now, generally be viewed as acceptable. Pretty sweeping things are thought to follow from this, including that it is quite possible that Kant is generally indulging in what the author refers to as "gobbedly-gook". (Like the reference to "bullshit" in the citation given in the previous posting it is intriguing to find philosophers using such terms as if they were, in some sense, state of art, that is, defined something.)
There are a number of things at issue here which are rather odd even assuming, as very likely, that Kant did make a number of "bad arguments" and defended things that should not have been defended as well as attacked a number of things that should not have been attacked. The first thing at issue concerns whether something of philosophical value arises when Kant, or any other confessedly "major" philosopher says something that, on reflection, seems clearly wrong. In the cases at issue in the posting there are remarks Kant makes concerning wives and servants, masturbation, organ donation, homosexuality, the killing of bastards and tyranny. Now, even before attempting to go into any detail here, the first point would be that the cases at issue here are quite varied. So, whilst the status of wives and servants has undoubtedly changed considerably since Kant was writing, the nature of that change has, amongst other important elements of it, reflected a sense of how "property in one's person" should be understood. This is no small change and grappling with the nature of that change might well be worth some philosophical time rather than simply thinking that the citation of a passage from the history of philosophy on this topic was sufficient to close down consideration of the question of whether this philosopher has made an important contribution to the area of philosophy in question.
Masturbation is a topic that concerns "duties to oneself" and, on this, I hope I am not immodest if I point to the discussion of this in my book Kant's Practical Philosophy as indicative of a way a serious approach to this topic can both bring out the means by which Kant's response here does draw on deep resources of his practical philosophy that point to the conclusions he draws whilst also enabling discussion of how a different conclusion could have been drawn. Without work of that kind I struggle to see how we can learn at all from the history of philosophy unless, that is, name-calling is thought an appropriate response to a position on which disagreement with historical positions is pretty manifest.
Organ donation remains a subject on which there are varied and serious philosophical options open and when Kant here tries to tackle the question of the boundaries of the self he is surely doing something important even should the way that he does it be thought problematic. It is hardly, in any case, a settled business this topic. No more is the topic of homosexuality even though the stand adopted here by Kant is one that would not tend to be adopted by Kantians today. That serious work on this area is decidedly necessary is manifest today and whilst I would certainly not want Kant's view here to become one widely adopted I would hope it worth attending to the rationale for what that view was. The question of resistance to tyranny and rebellion is a decidedly complex one that, once again, we do a disservice to if we simply reject Kant's position since here he does raise a serious problem about the basis of right.
Going through the cases is one thing, however, adjudicating the charge of "gobbledy-gook" quite another. This does, again, partly come back to questions of what "clarity" involves. The author of the posting I am here replying to seems to think it is "elitist" to write in a way that many people find difficult though it is hard to think of any philosopher who is not seriously difficult quite a lot of the time. That would, after all, be part of the point of being a philosopher! Another element of the charge made in the posting in question is that Kant can attain no greater insight on moral topics than anyone else, as is shown by his "bad" judgments on the topics in question. Now here there is surely some serious conflation. On the one hand there are the "judgments" of Kant, the guy. On the other, there is a question about what, if anything, is enduring in the body of works signed by this person. To infer from the view that the former misjudged things that the latter is untrustworthy is a sure fallacy. Secondly, the arguments cited from the Metaphysics of Morals are not all equivalent within the logic of the work since the discussion of homosexuality has no place in the strict position of right for example whilst that on tyranny and rebellion has a very important role there. Given this difference insight into the structure of the work and the basis of the positions in this structure would be of signal help in evaluating the results achieved. Amongst other points here would an assessment of how far Kant has followed his own guidelines for procedure in reaching his conclusions and what the general alternative positions, considered within that procedure, might well be. In fact, without work of that sort it is only by reference to previously assumed standards that the arguments can even be viewed as "bad".
Two last points. Even if none of the above compels conviction it would still be surely bizarre to find an extension from the passages cited to a general conclusion about Kant's work. There is no way any body of work can be treated in such a summary fashion. Finally, if there is any point to a notion of "common sense morality" then the relation of philosophy to it needs to be evaluated from both ends. That is, whilst philosophy should surely attempt to make such morality more explicit it should also provide a critical riposte to it. On the other hand, if there is a robust sense to such morality then it should, in its turn, provide an image by which to test philosophical criticism. So the relation should be mutual without it following that nothing particular has come from the philosophical end of the argument.