In contrast, the constructive empiricist holds that science aims at truth about observable aspects of the world, but that science does not aim at truth about unobservable aspects.
Dilating on each landmark (in speech bubbles), Gull alludes to the great London poet and artist William Blake, whose supposedly "mad prophecies and visions" amount, in Gull's admiring view, to an uncommon receptiveness to the hidden truths of observable reality.
A notable development of the latter approach is the constructive empiricism of Bas van Fraassen, according to which science aims not at true theories but at theories which are "empirically adequate," in the sense that they capture or predict relevant truths about observable matters.
Since mathematical entities do not, by themselves, have connections to observable phenomena, the question of truth and falsehood may not be put in a truth-conditional manner for those axioms that connect mathematical entities with phenomenal events (cf. Section 4.2).
So the constructive empiricist is firm in her construal of the aim of science as truth about the observable.
There are two types of probable truth: that which concerns observable matters of fact, and that which goes "beyond the discovery of our sense".
Hence, one can object to constructive empiricism by suggesting that it is not sufficiently epistemically modest: the doctrine that the aim of science is truth about what is observable should be replaced with the doctrine that the aim of science is truth about what's actually been observed.
Changing Direction In a Scholarly Battle This led him to fight in the ranks of the so-called logical positivists, or those like his European friends A. J. Ayer and Rudolf Carnap, who asserted that all statements of truth must be based on observable data.
Or, to take an example from psychoanalysis, the occurrences of unconscious wishes or conflicts are the truth conditions for which the observable symptoms (Freudian lapses, manifest dream contents, and the like) serve merely as indicators or clues i.e., as items of confirming evidence.
Although the programmed ground truth goal state is not directly observable, subjects' responses showed both high validity (correlation with this ground truth) and high reliability (correlation with one another).
