PHL220. The Deductive Nomological Method with Falsificationism
The Deductive Nomological Method with Falsificationism
A Simplistic view of Scientific Method
In scientific method, we sometimes use inductive generalization to
identify causal correlations. One way we can describe the process is:
Deductive Nomological Theory of Science, with Falsificationism
- The basic view:
- We observe (in our sample) that events of kind Q
follows events of kind P;
- We generalize that Qs always follow Ps (that is,
Qs follow Ps throughout our population, which is all
events, including future events);
- We say that Ps cause Qs.
- There are two problems with the basic view:
- Science posits that there is something underlying
the correlation of two events which allows us to say
that one causes another: the working of natural laws.
In other words, not all correlations are taken to be
- It is never clear which observations should be
made until we have a hypothesis about what
correlations we expect (that is, until we have a
hypothesis about natural laws).
The leading alternative is a more sophisticated view.
- We develop a hypothesis that there are certain natural
laws or certain effects of natural laws. These hypotheses
must be falsifiable: they must entail predictions which are
in principle testable and could be false.
- We predict some events which must occur if our hypothesis
is true (that is, what are some unexpected results such laws
or effects will have?).
- We check to see if these predictions come true; if
they do, we make inductive generalizations based on these
- We continue to try to falsify the view.
- Thus, for example:
- Suppose H is a hypothesis.
- We look to see what events H implies.
- If these predicted phenomena are observed to be
true, we continue to hold H as a hypothesis.
- We especially are inclined to consider H likely
if any of these consequences are unexpected.
- If any of the predicted consequences is observed
false, we reject the hypothesis.
- The "deductive" part here is the inference from hypothesis
to consequences. The "nomological" part is the presumption that
we are aiming to discover laws ("nomological" means reasoning
- A fantastic example includes Einstein's claims that gravity
warps spacetime. This was weird, unexpected, and so the predictions
were strange and unexpected.
- Some important corollaries of the deductive nomological
theory with falsificationism
- We cannot prove a theory, we can only show it is likely.
- Thus, we never know a theory is true (although we
can show that it is vastly superior to the
- Science is creative: you must come up with
hypotheses before you can apply scientific method.
- A scientific theory (that is, a theory about the
physical world, not a logical theory) which is not
falsifiable is a bad theory!
Why does it matter that a scientific theory must be falsifiable?
- What kind of claim is not falsifiable? Examples include:
Most are inclined to believe that what distinguishes these examples
is that they are true either in terms of meaning (analytic) or are
consequences of other premises (logical claims).
- All bachelors are unmarried males.
- A claim that is not falsifiable is typically an analytic
claim dressed up to look like a synthetic claim (a substantial
claim not just concerned with meaning or logic alone). Even
the person making the claim may be confused.
- Example: economists often claim all motivations are selfish.
Confronted with the observation that some people appear to do
altruistic things, they may say these people desire to do altruistic
things and so are selfish. But note: "selfish" on this kind
of view means nothing more than something like, does what one
wants to do. That is fine -- economists should be allowed to define
any terminology they want -- but it is a different meaning
than we usually use for "selfish." Furthermore, to say people
are "selfish" on this view is not to make a claim -- it is to state
an assumption that they make in all their reasoning!
- Unfalsifiable claims are thus usually presumptions, perhaps
vacuous, that are dressed up like substantive claims. Typically
even the person making the unfalsifiable claim is deceived by their
own terminology and misses the ambiguity.