Question

Read the following passage and answer the question that follows.

Attempting to understand science and scientific reasoning in terms of the subjective beliefs of scientists would seem to be a disappointing departure for those who seek an objective account of science. Howson and Urbach have an answer to that charge. They insist that the Bayesian theory constitutes an objective theory of scientific inference. That is, given a set of prior probabilities and some new evidence, Bayes' theorem dictates in an objective way what the new, posterior, probabilities must be in the light of that evidence. There is no difference in this respect between Bayesianism and deductive logic, because logic has nothing to say about the source of the propositions that constitute the premises of a deduction either. It simply dictates what follows from those propositions once they are given. The Bayesian defence can be taken a stage further. It can be argued that the beliefs of individual scientists, however much they might differ at the outset, can be made to converge given the appropriate input of evidence. It is easy to see in an informal way how this can come about. Suppose two scientists start out by disagreeing greatly about the probable truth of hypothesis h which predicts otherwise unexpected experimental outcome e. The one who attributes a high probability to h will regard e as less unlikely than the one who attributes a low probability to h. So P(e) will be high for the former and low for the latter. Suppose now that e is experimentally confirmed. Each scientist will have to adjust the probabilities for h by the factor P(e/h)/P(e). However, since we are assuming that e follows from h, P(e/h) is 1 and the scaling factor is 1/P(e). Consequently, the scientist who started with a low probability for h will scale up that probability by a larger factor than the scientist who started with a higher probability for h. As more positive evidence comes in, the original doubter is forced to scale up the probability in such a way that it eventually approaches that of the already convinced scientist. In this way, argue the Bayesians, widely differing subjective opinions can be brought into conformity in response to evidence in an objective way.



Using the idea explicated in the passage above, the only scientific way to deny the validity of a counter-hypothesis put forward to explain a natural phenomenon would be to:

• A. Take the counter-hypothesis and try to find flaws in its components.
• B. Question the source of alternative hypothesis.
• C. Question the authority of the scientist stating the alternative hypothesis.
• D. Take the alternative explanation and ask for its fullest development in terms of possible ramifications other than the already existent outcome (e).

Hint:

Recall that the passage says logic has nothing to say about where a hypothesis comes from; a hypothesis is judged by its predictions, not its source.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
We are told to use only the reasoning given in the passage, the Bayesian idea that a hypothesis h is judged by whether it predicts an outcome e that is then confirmed by evidence. The question asks how, strictly by this logic, one would scientifically reject a rival hypothesis that also tries to explain the same event.

Step 2: Key Approach:
Rule out any option that relies on something outside the hypothesis-evidence relationship described in the passage, such as the identity of the person proposing the idea or where the idea came from. The passage is explicit that the source of a proposition does not matter to this framework; only what the hypothesis predicts, and whether that prediction holds up, matters.

Step 3: Detailed Explanation:
Options that ask us to question the source of the rival hypothesis, or the authority of the scientist proposing it, fall outside the passage's logic entirely, since the passage says plainly that logic has nothing to say about the source of the propositions. Simply hunting for internal flaws in the counter-hypothesis is also not the method described; the passage's method is about testing predictions against evidence, not dissecting structure. What remains is the option that pushes the counter-hypothesis to predict something new, something beyond the single outcome e that already happened. This matters because a hypothesis invented to match evidence already in hand proves nothing on its own; almost any explanation can be built to fit a known fact after the event. The real test, in the spirit of the passage, is whether the rival hypothesis can predict fresh outcomes that can then be checked, the same way h is checked against e.

Step 4: Final Answer:
The answer is option 4: take the alternative explanation and ask for its fullest development in terms of ramifications beyond the outcome e that already exists. This is the only option that keeps the test within the evidence based, prediction driven method the passage lays out.