There are four categories of responses to this type of article. Each of these correspond to one of the four classical theories of truth. Let's examine each of them in turn, as an exercise in critical thinking.
Conversation
The first response is to evaluate the argument based on its argumentative structure. Do the conclusions flow logically and coherently from the premises? Are there inconsistencies or logical fallacies in the reasoning?
This is the coherence theory of truth.
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The coherence theory of truth states that a claim is true if it is logically coherent with all of its upstream propositions.
Basically, the whole 'Socrates is a man, all men are mortal, therefore Socrates is mortal shebang.'
On this basis, Milo's piece passes the bar for truth.
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His conclusions flow logically from his premises.
He argues that Progressive Summarisation is a lousier method because it produces thinkers who are uncritical and who regurgitate old ideas. His premise is that blind summarisation will not lead to novel insight.
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If we accept this premise as true, then everything else follows logically. There are no logical inconsistencies in his argument (that I can detect). So it passes the bar for truth with regard to coherence.
Thankfully, coherence is not the only theory of truth we have.
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The next theory is the correspondence theory of truth. That is, what is true is what corresponds to observed reality.
Here, the premises begin to fall apart. Is it true that summarisation leads to bad thinking? Are there examples or counter examples?
Indeed there are.
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Replying to
I’m sorry, but you don’t get to say that headnotes is proof of the benefits of summarisation, and not that of PS. PS is a superset method, which has more benefits than plain summarisation.
Whatever benefits summarisation has, PS has also. Proof: personal practice.