
Todd Lewis posted an update in the group Praxeological Science 9 months ago

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Propositional logic is not a complete system. That’s why we build predicate logic upon it and why we build other systems, like Peano’s theory of Numbers, upon predicate logic and why we build Real number theory on Number theory and incorporate real numbers in empirical systems like the standard model in Physics.
Godel showed that even a system as…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Propositional logic is not a complete system. That’s why we build predicate logic upon it and why we build other systems, like Peano’s theory of Numbers, upon predicate logic and why we build Real number theory on this theory and incorporate real numbers in empirical systems like the standard model in Physics.
Godel showed that even a system as…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Propositional logic is not a complete system. That’s why we build predicate logic upon it and why we build other systems, like Peano’s theory of Numbers, upon predicate logic and why we build Real number theory on this theory and incorporate real numbers in empirical systems like the standard model in Physics.
Godel showed that even a system as…[Read more]

Matthew Reece replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
They are using such statements conditionally rather than universally, which is why they can get away with this. Propositional logic can be applied to such statements, but the statements usually must be broken into simple component parts first.

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Contradicting a tautology leads immediately to a contradiction in a system incorporating the tautology, because a tautology is “true” by definition. For example “P or not P” is a tautology in propositional logic. Its contradiction is “P and not P”, but this statement cannot be true if “P” is a valid proposition, because “propositions” in…[Read more]

Matthew Reece replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
I am not sure that the two can be separated because attempting to argue against a tautology should result in a contradiction.

Martin Nicholls replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Interesting quote I think fits nicely:
“[Sweeps plate of cookies off table] maybe you knew I was going to do that, maybe you didn’t. If you did, that means you baked those cookies and set that plate right there deliberately, purposefully. Which means you’re sitting there also deliberately, purposefully.”
Agent Smith: The Maxtrix Revolutions. 
Martin Brock replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
You assume that the arguer has a purpose in making the argument because he makes the argument. A spider or a robot similarly has a purpose. Purposefulness is true tautologically rather than the consequence of some proof by contradiction.

Bruce Koerber replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Purposefulness is a means and it is an ends and so it falls within the science of economics and the science of ethics for further analysis and since both of these sciences are part of the realm of the human science the proper methodology for analysis is subjectivism. It is very possible, then, to prove that people are purposeful.

Martin Nicholls replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
What do you suppose Kirzer’s purpose in making that argument was? Using his example of running to catch a bus, it doesn’t seem plausible that the purpose of the actor is just simply running for exercise… next to or just behind a bus. We of course cannot completely know what the purposes of an individual are because like our values they are…[Read more]

Matthew Reece replied to the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
It is difficult to prove that people have a particular purpose. But to argue that people are not purposeful is a performative contradiction because the arguer has a purpose in making the argument.

Martin Nicholls started the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Came across this video last night of Israel Kirzner giving a new lecture on the history of the Austrian School, but he gave an interesting response in the Q&A session on logical deduction.

Martin Nicholls started the topic Kirzner: "It's difficult to prove people are purposeful" in the forum Praxeological Science 3 years, 6 months ago
Came across this video last night of Israel Kirzner giving a new lecture on this history of the Austrian School, but he gave an interesting response in the Q&A session on logical deduction.
I posted some question’s about the business cycle a few days ago, if anyone is interested.