Astronomy clicker question: Drake equation anti-pessimists

Astronomy 10, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal F.2

Students were asked the following clicker question (Classroom Performance System, einstruction.com) in the middle of their learning cycle.

[0.3 points.] The Drake equation may predict that the Milky Way has only one advanced technological civilization (us). Which argument against this extremely pessimistic result do you consider most valid?
(A) Absence of evidence (of the existence of other advanced technological civilizations) is not evidence of their absence.
(B) It is not very likely we are that special.
(C) Given the vast number of stars in the Milky Way, over a vast amount of time, a very small probability that an advanced technological civilization would arise can result in a sizeable number.
(D) (More than one of the above arguments.)

Correct answer: (none; opinion only)

Each of these arguments was explained to the class before this question was asked. Item (A) is the observation that a null result cannot disprove a hypothesis; (B) is the Mediocrity Principle ("Copernicanism"); and (C) is the Scale Argument ("playing the odds").

Student responses
Section 4160
(A) : 11 students
(B) : 3 students
(C) : 15 students
(D) : 3 students

Section 5166
(A) : 11 students
(B) : 8 students
(C) : 23 students
(D) : 3 students