The Problem of Induction 1

Can the principle of induction be justified?

1. According to the naive inductivist, science starts with observation, observation supplies a secure basis upon which scientific knowledge can be built, and scientific knowledge is derived from observation statements by induction.

2. In this chapter, doubt will be cast on the validity and justifiability of the principle of induction.

3. The following is the basic principle of induction on which science is founded: “If a large number of A’s have been observed under a wide variety of conditions, and if all those observed A’s without exception have possessed the property B, then all A’s possess the property B.

4. Why it is that inductive reasoning leads to reliable and perhaps even true scientific knowledge?

5. The inductivist might try to justify the principle by appealing to logic or he might attempt to justify the principle by appealing to experience.

6. Valid logical arguments are characterized by the fact that, if the premise of the argument is true, then the conclusion must be true. However, inductive arguments do not possess this character.

7. It is possible for the conclusion of an inductive argument to be false and for the premises to be true and yet for no contradiction to be involved.
- A large number of ravens had been observed under a wide variety of circumstances and all of them have been black. On that basis, it is concluded, “All ravens are black.”
- There is no logical guarantee that the next raven be observed will not be pink. If this proved to be the case, then “All ravens are black” would be false.

8. Induction cannot be justified purely on logical grounds.

9. The inductivist would indicate presumably like this; induction has been observed to work on a large number of occasions. In this way, the principle of induction is justified.

10. The argument purporting to justify induction is circular because it employs the very kind of inductive the validity of which is supposed to be in need of justification. The form of the justificatory argument is as follows:
- The principle of induction worked successfully on occasion x1
- The principle of induction worked successfully on occasion x2 etc
- The principle of induction always works

11. The argument is therefore an inductive one and so cannot be used to justify the principle of induction. We cannot use induction to justify induction.

12. In addition, the principle suffers from other shortcomings which stem from the vagueness and dubiousness of the demand that a “large number” of observations be made under a “wide variety” of circumstances. How many observations make up a large numbers? What is to count as a significant variation in the circumstances?

13. It would take a very stubborn inductivist to put his hand in a fire many times before concluding that fire burns. In circumstances like these, the demand for a large number of observations seems inappropriate. It other situations, the demand seems plausible
- We would justifiably reluctant to ascribe supernatural powers to a fortune-teller on the basis of just one correct prediction.

14. What is to count as a significant variation in the circumstances? The variations that are significant are distinguished from those that are superfluous by appealing to our theoretical knowledge of the situation and of the kinds of physical mechanisms operative.
- When investigating the boiling point of water, is it necessary to vary the pressure, the purity of water, the method of heating and the time of the day?
- “Yes” to the first two, but “No” to the second two. But what are the ground of these answers?

15. To admit this is to admit that a theory plays a vital role prior to observation. The naïve inductivist cannot afford to make such an admission.

Summarized from:
Chalmers, A. Francis. (1982). What is this thing called science?. St. Lucia, Queensland: University of Queensland Press. (Chapter 1)



Executive Committee of Academic and Intellectual
Session of 2009/2010