“You cannot step in the same river twice”

I find fallacies intriguing. That’s why I have treated them already several times in these blogs. Fallacies are incorrect reasonings and sooner or later everybody makes mistakes of this kind. Even philosophers, scholars and scientist do. So a good reason to keep paying attention to them. As before, I make extensive use here of Arp, et al., 2019 (see Reference). Here is their full definition of a fallacy:
“A fallacy is an error in reasoning whereby someone attempts to put forward an argument whereby a conclusion supposedly has been appropriately inferred from a premise (or premises) when, in fact, the conclusion does not and should not be inferred from the premise(s).” (p. 19; italics in the original)
Fallacies are errors and should be avoided. They are based on false facts or views and usually the conclusion is a false fact or view (although it remains possible that the conclusion of a false reasoning happens to be true despite the false reasoning). However, it’s often not noticed that a reasoning is false and fallacies can have long lives. Some fallacies may have been put forward while those who did simply thought that the reasoning was correct, but it also often happens that false reasonings are put forward on purpose by people who think to gain by doing so and who want to manipulate people. Especially in politics both things happen, and maybe the latter more than the former, but that’s a personal opinion that I cannot substantiate with facts. Anyway, beware of politicians who use rhetoric.
Fallacies can be divided into formal and informal fallacies. A formal fallacy is one in which the conclusion doesn’t follow from the premise(s) because of errors in the structure (form) of the reasoning, rather than in the content. The fallacy called “affirming the consequent” is a case in point, for instance: “If it is raining, the sidewalk is wet. > The sidewalk is wet, so it is raining”. The conclusion doesn’t follow, for maybe someone has just scrubbed the sidewalk. This simple fallacy is committed more often than you think!
An informal fallacy is one in which the conclusion doesn’t follow from the premise(s) because of errors in the content of the reasoning. Since the content is expressed in language, often we find the false reasoning in the language used, like the misuse of words or grammar, false understanding, vague use of conceptions, and so on. Prejudices belong to this type of fallacy, for instance: Someone did something wrong and then the reasoning is “it is because s/he is a person from that ethnicity/sex/creed and my experience is that such persons behave that way.” (cf. Arp, et al., 2019, pp. 18-27) Arp et al. discuss seven formal fallacies and 93 informal fallacies, but it’s only a selection.
Also schooled thinkers commit fallacies. Even the Old Greek philosophers did, although they introduced the idea of fallacy in Western philosophy. By way of example, I’ll discuss here a statement by Heraclitus (540-480 B.C.). Fallacies were first systematized by Aristotle (who lived after Heraclitus, namely from 384-322 B.C.; click here for his work on fallacies), but I think that fallacies were certainly already known to Heraclitus.
Last year in a blog (click here; at the end) I shortly discussed Heraclitus’s statement that you cannot step into the same river twice. I explained that in this statement Heraclitus confused levels, namely the levels of the river and the water, and that you can step into a river as often as you like. We can also say that Heraclitus committed the fallacy of composition. The river consists of a bed in a landscape and this bed contains streaming water, indeed. However, it is not so that the river itself streams but that the water in the river streams. As such the river has a fixed place in the landscape and keeps this place when you cross it. If we say that a river streams, it is only a metaphor, a figure of speech that means that the water in the river streams. So, if we say “a fast-flowing river”, in fact we mean that the water in the river is fast-flowing. Therefore, you cannot step into the same (river) water twice, but you can step in the river itself as often as you like. The fallacy of composition is the error to ascribe characteristics, attributes or features of a part to the whole it belongs to, and this is what Heraclitus did: streaming is a characteristic of the water in the river but not of the river itself. (cf. Arp, et al., 2019, pp. 250-1; the example is mine)
Now it is up to you to uncover the fallacies that I committed in my blogs. 

Reference
Arp, Robert; Steven Barbone; Michael Bruce (eds.), Bad arguments. 100 of the most important fallacies in Western philosophy. Oxford, etc.: Wiley Blackwell, 2019.