Homework help: falsificationism and existential statements

Reply to Varun Soontornniyomkij From what I remember, isolated existential statements contain a universality and sometimes can add context or meaning to a statement that changes the falsifiability and thus make it scientific. On it's own, however, it cannot be anything but unfalsifiable, a type of broad metaphysical meaninglessness, but it can be given meaning when we remove this isolation by applying it to something specific. So, "some mammals lay eggs" can be falsifiable if we think about a platypus.

I think the way I would go would be to say that "some mammals lay eggs," is scientific, but not a theory but a fact, that falsifies the theory, "No mammal lays eggs". This theory was actually taken to be true until the discovery of the platypus, which caused a deal of argument and annoyance to biologists of the time.

In terms of simple logic, 'Some' has existential import, which means it reports a fact, whereas 'all' does not, and reports a theory.

The discovery of the platypus by Europeans resulted in a major re-think about the classification of vertebrates and our understanding of the evolution of mammals. The story of the investigation of the platypus reveals a lot about the processes of science. Rivalries, competition and collaboration occurred between groups and across countries. Prior conceptions and understandings were challenged, and some workers were slow to accept the new contradictory evidence.

From here.

Reply to Varun Soontornniyomkij
"Some mammals lay eggs" might count as an observation rather than a theory. It would be an observation that falsifies the universal claim "No mammals lay eggs."

@unenlightened okay that was weird.

An unfalsifiable claim is scientific if it's deducible from a falsifiable claim. Such a falsifiable claim could be "this is a mammal and it has laid an egg".

Putting Michael's input in other words: Look at all known examples of mammals, and if all of them do not lay eggs, then the claim "some mammals lay eggs" will have been falsified.

Also relevant, from here:

The Popperian criterion excludes from the domain of science not unfalsifiable statements but only whole theories that contain no falsifiable statements

The particular statement "some mammals lay eggs" might not be falsifiable but that doesn't preclude it from being scientific.

Reply to Michael Platypus is a mammal and it has laid an egg is better.

Reply to VagabondSpectre
As a matter of logic, sure, but this is not really in the spirit of the enterprise, is it?

We want to avoid claims that could only be falsified by observing every member of a class. The claims we want are ones that would generate readily testable predictions. "If it comes up blue, my theory is false," rather than, "Only another 10,000 to go."

Can we even presume we can make every needed observation in this way? When you refer to "all known examples of mammals" isn't that a pretty risky way to carve out a class?

Still, you're right about there being a kind of symmetry here, and that makes me wonder if the falsifiability criterion can be made to carry the whole load.

Quoting Varun Soontornniyomkij

The goal is to defend falsificationism (as formulated my Karl Popper) from this criticism:
Theories that contain existential statements, such as "some mammals lay eggs," are not falsifiable, but the one I mentioned above seems perfectly scientific.

I think I'm missing the point. Why would I pick a statement known to be true as an example of one that is not falsifiable?

Reply to Varun Soontornniyomkij

According to Popper it doesn't count without a when and where, that's what makes it checkable. So "some mammals lay eggs, in eastern Australia in contemporary times" is falsifiable, but just "some mammals lay eggs" itself isn't, it isn't bounded enough, it could be in another solar system.