Certainty and How to Do Without It
I. Hume's argument against induction. An Inquiry Concerning Human Understanding (Section IV, Part II) There can be no rational basis for the belief that similar causes will have similar effects.
A. All reasoning must consider either (1) relations of ideas; or (2) Matters of fact.
B. No argument can be drawn from relation of ideas, that is from the concept or essence of the cause to the necessity or probability of the effect. The essence of the cause is never found to contain the effect as can be shown from the fact that there is no contradiction involved in thinking the cause without the effect.
C. No argument can be drawn reasoning about matters of fact, for all knowledge of matters of fact comes from experience. All such arguments for induction must necessarily be circular, since this assumes what is to be proven, namely that similar causes will continue to have similar effects. Hence, the fact that A has been followed by B in the past can provide no argument that it will continue to do so, unless one assumes that the future will resemble the past, which is precisely what is at issue.
II. Refutation: You can base a rational expectation that similar things will act similarly, not on an analysis of the essence of the object, not on experience of its actions, but based upon a use of reason in its transcendent function.
A. Identicals will act identically under identical conditions. This follows from the law of non-contradiction. Not merely from the fact that if A has property P that B will have P if A=B, but more precisely from the law as applied to situations. To say that A=B and that situation S1, which contains A, is identical to S2, which contains B, is to say that all the things that follow from A must follow from B by the law of non-contradiction. (The key assumption here may be the inseparability of cause and effect within a situation.)
B. A situation may be analyzed as a collection of elements. Similar situations are those that have many identical elements. Hence, by the previous premise, similar situations will have many elements which act identically. Hence the more elements that are identical (the more similar) two situations are, the more likely it is that they will act similarly, given that their actions are a sum of the actions of their elements. Probability theory and scientific method, rightly viewed, are based upon this principle.
III. Living without certainty: Assuming that the previous argument fails (and can we say with certainty that it does not?) as well as all others? Can reason provide us with a guide to life? Is philosophy useful if it provides no certain knowledge of the world? Is there a wisdom that is more than knowledge, and which is useful in the absence of knowledge.
A. Hume identifies four basic approaches to happiness in the absence of certainty. (These are from his series of 4 essays on the Epicurean, the Stoic, the Platonist, and the Sceptic, Essays xv-xviii in Hume’s Essays, Routledge & Sons)
1. Epicurean. What is certain is pleasure and pain. Seize the moment and pursue consistent and stable pleasure.
2. Stoic. Nature provides certain restrictions on our pleasure. Use Reason and Habit to accommodate ourselves to nature and correct for the vulnerability of our happiness.
3. Platonist: Only the mind is certain. Pursue contemplation of the highest and most eternal aspects of mind.
4. Skeptic. We cannot tell which ends are truly the best, but we can generate certain general maxims that will serve all ends. For example, pursue those passions that tend to be moderate, social, hopeful, steady.
B. These can a be further organized into two groups:
1. Stoic/Skeptic: Those that use the transcendent function of reason to generalize over all possible cases to pursue what would be useful to any ends or conception of happiness whatsoever. Kant's Categorical imperative represents the culmination of this method.
2. Epicurean/Platonist. We can be certain only of the contents of experience, but if we us the self-reflexive capacity of reason to examine experience and reason itself. We can find a happiness within the activity of rational self-consciousness itself.
Of the uncertainty after all, that we may be deluded,
That may-be reliance and hope are but speculations after all,
That may-be identity beyond the grave is a beautiful fable only,
May-be the things I perceive, the animals, plants, men, hills,
shining and flowing waters,
The skies of day and night, colors, densities, forms, may-be these
are (as doubtless they are) only apparitions, and the real
something has yet to be known,
(How often they dart out of themselves as if to confound me and mock
How often I think neither I know, nor any man knows, aught of them,)
May-be seeming to me what they are (as doubtless they indeed but
seem) as from my present point of view, and might prove (as
of course they would) nought of what they appear, or nought
anyhow, from entirely changed points of view;
To me these and the like of these are curiously answer'd by my
lovers, my dear friends,
When he whom I love travels with me or sits a long while holding me
by the hand,
When the subtle air, the impalpable, the sense that words and reason
hold not, surround us and pervade us,
Then I am charged with untold and untellable wisdom, I am silent, I
require nothing further,
I cannot answer the question of appearances or that of identity
beyond the grave,
But I walk or sit indifferent, I am satisfied,
He ahold of my hand has completely satisfied me.