An "observation statement" is one that records an actual or possible observation (like "The arrow points to the number 5"). Ayer requires of a genuine factual proposition that
An "observation statement" is one that records an actual or possible observation (like "The arrow points to the number 5"). Ayer requires of a genuine factual proposition that
This violates scientific practice. Science recognizes statements like "This battery has 1.5 volts" (and other statements about unobservables) as meaningful. But "This battery has 1.5 volts" isn't itself an observation statement.
An "observation statement" is one that records an actual or possible observation (like "The arrow points to the number 5"). Ayer requires of a genuine factual proposition that
"The battery has 1.5 volts" is a genuine factual proposition -- since it, together with other premises, entails "The arrow on the voltmeter points to 1.5," without the latter being deducible from the other premises alone.
In short, genuine factual propositions have testible consequences -- but sometimes we have to add other premises to derive these consequences.
An "observation statement" is one that records an actual or possible observation (like "The arrow points to the number 5"). Ayer requires of a genuine factual proposition that
This violates scientific practice. Science recognizes statements like "This battery has 1.5 volts" (and other statements about unobservables) as meaningful. But "This battery has 1.5 volts" doesn't by itself logically entail any observation statements.