“How to Makes Our Ideas Clear” by Charles Sanders Peirce

Citation: Peirce, Charles. 1878. “How to Make Our Ideas Clear.” Popular Science Monthly 12, 286-302

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In How to Make Ideas Clear, Peirce argues that we understand ideas clearly when we understand the idea’s “sensible effects.” However, prior to advancing this notion, he describes how philosophers have described “clear ideas” in more narrow terms, first as familiarity, then as distinctness (e.g. Descartes and Leibnitz’s formulations).

He makes his argument in four parts, first describing prevalent conceptions of what is required for clear ideas and how they fall short; second, describing the proper method that is needed, i.e. considering what effects the idea has; third, he provides examples; and fourth, he applies his method to making the idea of “reality” clear, arguing that the only effect of real things is to cause belief.

In part one, he discusses two properties logicians use: clearness and distinctness (nothing unclear about them). Says they’re poorly understood. He wants to move beyond thinking of clearness as familiarity. Descartes failed to differentiate between things “seeming” to be clear and actually being clear. Leibnitz recognized Descartes’ flaw but reverted to trivialities of logic, i.e. futile abstractness. These unclear notions of clarity are problematic; as Peirce notes, a few clear ideas are worth more than many confused ones. His key point in this section is that familiarity is an important part of clarity, but there’s a “higher perspicuity of thought”.

In part two, he talks about reaching clearness of thought of a higher grade than distinctness. He notes that production of belief is the sole function of thought. Action of thought is excited by irritation of doubt and dampened by attainment of belief. So the key point is that however doubt originates, it stimulates the mind to an activity, helping us decide how we should act, moving us toward attaining beliefs. Belief has 3 properties: (1) aware of it, (2) appeases irritation of debt, (3) establishes habits. So our idea of anything is our idea of its sensible effects. To get to a higher grade of clearness, we need to consider what effects the idea has. Then our conception of these effects is the whole of our conception of the object.

Part three gives various examples about “hard”, “weight”, “force”, etc. With regard to current attempts to make the idea of “force” clear, he quotes argues that the following statement that has been made regarding force is fraught with contradictions: “we understand precisely the effect of force, but what force itself is we do not understand.”

Finally, part four, he focuses on reality. “The only effect which real things have is to cause belief, for all the sensations which they excite emerge into consciousness in the form of beliefs.” He criticizes method of tenacity, authority, a priori (can’t introduce them with new facts; think belief can never be settled). Only method of science introduces us to new facts. The opinion which is FATED to be ultimately agreed by all who investigate, is what we mean by the truth, and the object represented in this opinion is real. That’s how he explains reality.


In my view the first part of Peirce’s argument should be separated from the latter three parts. Peirce argues in part one that philosophers, specifically logicians, are in an “intellectual slumber,” and while a priori philosophy, as espoused by Descartes and Leibniz, had its merits over methods that it replaced, i.e. method of authority (more directly explicated in The Fixation of Belief), suffered from severe limitations. However, this critique is not properly developed. He essentially argues, with respect to Descartes, that men cannot separate true beliefs from what they are inclined to belief, and so to define the standards for “clear ideas” in terms of a mind that is independent of experience is fundamentally problematic. This, in my view, is a proper critique of an extreme version of rationalism. A softer version of the a priori method is that priors or “innate ideas” ought to be fleshed out through self-consciousness and introspection to the extent possible, but that they are indeed very limit in number and substance, which makes their fleshing out, in the absence of a “feeding of sensory experience” (my quote), quite limited.

However, all of this is orthogonal to the more truly pragmatist propositions articulated in parts two, three, and four, particularly two. Indeed, I would argue that many of the classical pragmatists were combatting a rationalist zeitgeist that preoccupied their thinking in ways that colored, and sometimes obfuscated, their articulation of pragmatism. The key insight of this piece, articulated in part two, and put into practice in parts three and four, is that the “whole function of thought is to produce habits of action,” and it follows from that that it comes down to “what is tangible and what is conceivably practical as the root of every real distinction of thought, no matter how subtle it may be.” Put differently: “our idea of        anything is our idea of its sensible effects.”

This proposition is at the core of pragmatist thinking and is cogently advanced in this piece. I think it’s important for contemporary scholars not to get bogged down in rationalist versus empiricist debates of the late 19th century and early 20th century. It is true that these debates exist today in different forms, particularly with respect to theories of action, but it could be argued that spending too much time with them betrays the pragmatist spirit. And it is also true, I think, that the strength of Peirce’s argument that ideas should be elucidated in terms of their effects is not strengthened/weakened by whether a priori approaches are “right or wrong.” Those philosophical questions, of course, have bearing in their most extreme forms, but nowhere else.

–Submitted by: Mazen Elfakhani | Harvard University | Sociology Department | Graduate Student Personal Website


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