Notes on Paul Meehl’s “Philosophical Psychology Session” #03

These are the notes I made whilst watching the video recording of Paul Meehl’s philosophy of science lectures. This is the third episode (a list of all the videos can he found here). Please note that these posts are not designed to replace or be used instead of the actual videos (I highly recommend you watch them). They are to be read alongside to help you understand what was said. I also do not include everything that he said (just the main/most complex points).

Theories of truth

Descriptive discourse: what is.

Prescriptive discourse: what should be.

Science is descriptive, ethics/law etc. Is prescriptive. Philosophy of science (metatheory) is a mixture of both and has to be so in order to properly work (which the logical positivists didn’t realise).

External history of science (domain of the non-rational). What effects politics, economics etc. had on a theory.

Internal history of science (domain of the rational). Whether a fact had been over-stated or how the theory interacted with other facts and theories.

Context of discovery: psychological and social q’s about discoverer. E.g. Discovery of benzene ring. The fact he “dreamed of the snakes” is irrelevant to the truth of the story (the justification).

Context of justification: evidence, data, statistics.

Some say there shouldn’t be a distinction, BUT: Just because there is twilight, doesn’t mean that night and noon are not meaningful distinctions.

There are grey areas e.g. A finding that we are hesitant to bring into the corpus.

Sometimes we have to take into account the researcher who has produced this finding e.g. Dayton-Miller and aether.

Unknown/unthought of moderators can have a significant impact. Don’t have to be a fraud to not include that in manuscript

Fraud is worse than an honest mistake because it can obfuscate and mislead as you have something in front of you. You need enough failed replications to say “my theory no longer needs to explain this”. But this is why taking into account context of discovery is important (even when in context of justification); how close to a person’s heart/passion/wallet is this result? These things won’t be obvious in the manuscript but can have an impact.

4 examples of context impacting research:
How strongly does someone feel about this result? How much is their wallet being bolstered by this finding?
Literature reviews also need to have the context of discovery considered. Reviewer may not be a fraud, may be sloppy, original paper may be poorly written. Meta-analysis counter-acts some of these flaws with some counterbalancing taking place that’s hard to do in your head. Meehl 1954 (psychologist is no better at weighing up beta-weights than the clinician). Can be abused.
File-drawer effect BUT also what kind of research is being funded because it’s popular/faddish? University gets in habit of having large pot of money from government to fund research. Doing research to get grants can mean a narrowing of research but also some research can be shelved by not being funded because it could turn up unwanted/uncomfortable results.- Politics of discovery.
When reading a paper, you don’t know how much politics/economics has influenced it/caused it to be researched in the first place and stopped other (potentially contradicting) research being conducted. Affects distributions of investigations. If a certain theory is favoured by the use of questionnaires rather than lab experiments and the former is used due to convenience, skewed picture.
Relying on clinical experience rather than data, their clinical judgements made during observation are highly influenced by their own personal theory (experimenter effects).
Power function is low, null result doesn’t tell you as much as a positive result.
Context of discovery is also impacted by context of justification e.g. Knowing logic means you are likely to avoid making a logical fallacy when examining research. Not all impacts will be negative.


Scientific realist: there is a world out there that has objective qualities and it is the job of science to work them out.

Instrumentalism: the truth of something doesn’t matter if it has utility.

But fictions can be useful.

B.F. Skinner believed that when we could test mental processes and not just infer them, then it would become apparent which processes map on to which area.

3 main theories of truth: correspondence theory of truth (view of scientific realist, that the truth of a statement is determined by how accurately it corresponds with the real state of affairs), coherence theory (truth consists of the propositions you have hanging together), and instrumental theory (fictionist, truth is what succeeds in predicting or manipulating successfully).

Scientific realists admit that instrumental efficacy bears on their truth. Part of the data.

Incoherent theory is false by definition, coherent theory can be false.

Caesar crossed the Rubicon (for correspondence): only 1 fact needed to verify; whether he crossed or not. Quine corners denote the subject of the sentence e.g. ‘Caesar crossed the Rubicon’ (first half of the sentence is meta-language) is true if and only if Caesar crossed the Rubicon (no quine corners + in the object language).

What grounds do we have for believing (epistemological)? *verisimilitude* What are the conditions for that belief to be correct (ontological)? Equivalent in their content, so if one is true then the other is true/if one is false then the other is false.

Semantic concept of truth.

Knowledge is JUSTIFIED true belief (so stumbling on to a truth by chance is not knowledge).

Truth is a predicate of sentences and not things.

Argument among logical positivists that they should remove the use of the word truth for empirical sciences as you can never be totally certain that what you’ve said is true (remove from meta-language). Only those predicates which we can be certain are accurate are permissible BUT that means you remove pretty much every word in language (all scientific language and most concrete language)

Verisimilitude (similarity to truth) is an ontological rather than epistemological/evidentiary concept (cannot be conflated to probability).

Scientific theories are collections of sentences and as such can have degrees of truth.


Yonce, J. L., 2016. Philosophical Psychology Seminar (1989) Videos & Audio, [online] (Last updated 05/25/2016) Available at: [Accessed on: 06/06/2016]<!– 1517653388406 –>

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