Locke’s Populist Logic

Again, your lordship [Stillingfleet] charges me, that I do not place certainty in syllogism; I crave leave to ask again, and does your lordship? … And if you do, I know nothing so requisite, as that you should advise all people, women and all, to betake themselves immediately to the universities, and to the learning of logic, to put themselves out of the dangerous state of scepticism: for there young lads, by being taught syllogism, arrive at certainty; whereas, without mode and figure, the world is in perfect ignorance and uncertainty, and is sure of nothing. The merchant cannot be certain that his account is right cast up, nor the lady that her coach is not a wheelbarrow, nor her dairymaid that one and one pound of butter are two pounds of butter, and two and two four; and all for want of mode and figure; nay, according to this rule, whoever lived before Aristotle, or him, whoever it was, that first introduced syllogism, could not be certain of any thing; no, not that there was a God, which will be the present state of the far greatest part of mankind (to pass by whole nations of the East, as China and Indostan, &c.) even in the Christian world, who to this day have not the syllogistical methods of demonstration, and so cannot be certain of any thing.

John Locke, Mr. Locke’s Reply to the Right Reverend the Lord Bishop of Worcester’s Answer to his Second Letter: Wherein, besides other incident Matters, what his Lordship has said concerning Certainty by Reason, Certainty by Ideas, and Certainty by Faith; the Resurrection of the Body; the Immateriality of the Soul; the Inconsistency of Mr. Locke’s Notions with the Articles of the Christian Faith, and their Tendency to Scepticism; is examined (1699), vol. 4, pp. 386-387 in the 1823 edition of Locke’s Works.

To post-Fregean ears, it is perhaps strange to hear that Locke’s Essay was, in the decades following its publication, regarded as a logic manual. Not only does the Essay (obviously) lack any treatment of symbolic logic, it doesn’t even give much attention to the question of validity or proper syllogistic form. At this time, however, logic was understood (as the subtitle of the Port-Royal Logic has it) as “the art of thinking.” Logic in this sense was something more like what philosophers today call normative or regulative epistemology: it was the study of how to use our cognitive faculties in such a way as to gain knowledge, or at least (perhaps especially, in Locke’s case) a degree of belief that is appropriately proportioned to the evidence.

Stillingfleet clearly reads Locke this way, for he is forever speaking of Locke’s method or way of certainty by ideas. He presents Locke as claiming to have discovered a new method of employing our cognitive faculties to gain knowledge (certainty), in a fashion that is inconsistent with what people had been doing before.

Locke, however, strenuously objects to this characterization in many places (including the quotation above). Locke repeatedly insists that, although the modern use of the word ‘idea’ may be due to Descartes and so (relatively) new, there is nothing new about the path to certainty he describes in the Essay. Back in his reply to Stillingfleet’s first answer, Locke insists that “if [the account given in the Essay] be new, it is but a new history of an old thing. For I think it will not be doubted, that men always performed the actions of thinking, reasoning, believing, and knowing, just after the same manner that they do now; though whether the same account has heretofore been given of the way how they performed these actions, or wherein they consisted, I do not know” (p. 135). This ‘history’, Locke says, is a description of the actions of his own mind, and his justification for publishing it lies in the assumption that other minds perform similar actions to his (pp. 138-9 and 143-5).

However, Locke’s own description of the Essay as a work of (natural) history—i.e., a mere description—is not inconsistent with its status as a logic—i.e., a work aimed at improving our thinking. The model for taking these things together is the Port-Royal Logic (1662), a work whose influence on Locke is well-documented. In the Preface to that work, the authors (Arnauld and Nicole) give the following account of the aims of logic:

… this art [of thinking, i.e. logic] does not consist in finding the means to perform [mental] operations, since nature alone furnishes them in giving us reason, but in reflecting on what nature makes us do, which serves three purposes.

The first is to assure us that we are using reason well, since thinking about the rule makes us pay new attention to it.

The second is to reveal and explain more easily the errors or defects that can occur in mental operations. For we frequently discover by the natural light of reason alone that some reasoning is fallacious without, however, knowing why it is so…

The third purpose is to make us better acquainted with the nature of the mind by reflecting on its actions (p. 23 of Buroker’s translation).

Arnauld and Nicole hold, as Locke does, that logic is in the first place descriptive because the ability to perform various cognitive operations is part of our natural endowment. The procedure, then, is to examine the functioning of human minds in order to understand the errors to which they are liable and, ultimately, to improve cognitive performance. To use an analogy, studying logic is more like athletic training than it is like learning to cook. It’s not a matter of learning to follow a new set of recipes, algorithms, or procedures, it’s a matter of practicing and training to hone a set of abilities naturally possessed by human beings.

To this end, Locke claims (still following Port-Royal, and both of them following Descartes), syllogisms and logical axioms are almost totally useless. As Arnauld and Nicole suggest, “those who could not recognize a fallacy by the light of reason alone would usually not be able to understand the rules behind it, much less to apply them” (Buroker, p. 135), and (as we saw in my last post) Locke makes basically the same case regarding maxims/axioms.

There is, however, a further line of argument, which is quite explicit in the quote at the top of this post, and is my reason for using the word ‘populist’ in the title: ordinary people, who haven’t been given a ‘Scholastic’ education and have never heard of Aristotelian syllogisms or maxims/axioms are perfectly capable of reasoning and gaining knowledge. It follows from that explicit awareness and employment of this method is not the primary or only basis for reasoning or knowledge. Of course, particular self-evident truths fall under universal maxims, and particular instances of good reasoning fall under syllogistic rules. But these are descriptive generalizations drawn by the philosopher trying to understand the human mind; they are not (or at least not ordinarily) tools employed in reasoning. This can be seen as a kind of externalism, holding that one can follow a rule of reasoning without having knowledge of the rule (see “How Berkeley’s Gardener Knows his Cherry Tree”). This kind of externalism has a populist basis: it is supported (in part) by Locke’s insistence that the dairymaid needs no help from Aristotle in order to be capable of reasoning and knowledge.

(Cross-posted at blog.kennypearce.net.)