Ungraspable mind

The Diamond Sutra says that ‘Past mind cannot be grasped, present mind cannot be grasped, and future mind cannot be grasped.’ (For an extended elucidation of this, see Dogen's ‘Shin fukatoku’ (Heine 1994, 153-6; Nishijima and Cross 1994, 189-205)). Perhaps Peirce is pointing in the same direction when he says that a sign must generate an interpretant in order to function as a sign (i.e. to enter into a real relation with its object), and beyond that, the interpretant in turn must function as another sign in the same relation to that object, and so on ad infinitum. This is the triadic nature of all genuine signs. Knowing and thinking, cognition and representation, being continuous relational processes, necessarily take time, and thus cannot be pegged to any specific location in time or space.

At no one instant in my state of mind is there cognition or representation, but in the relation of my states of mind at different instants there is. [note by CSP: Accordingly, just as we say that a body is in motion, and not that motion is in a body we ought to say that we are in thought and not that thoughts are in us.]

— (EP1:42)

Just because thinking is unstoppable, and mind ungraspable, does not imply that the object of cognition, or thought, is itself unreal. The laws of nature really do govern what actually happens and are not merely ‘results of thinking’, as ‘conceptualists’ believe. Peirce considered this doctrine a form of nominalism, and thus rejected it, as the scholastic realists had several centures earlier:

The great realists had brought out all the truth there is in that much more distinctly long before modern conceptualism appeared in the world. They showed that the general is not capable of full actualization in the world of action and reaction but is of the nature of what is thought, but that our thinking only apprehends and does not create thought, and that that thought may and does as much govern outward things as it does our thinking. But those realists did not fall into any confusion between the real fact of having a dream and the illusory object dreamed. The conceptualist doctrine is an undisputed truism about thinking, while the question between nominalists and realists relates to thoughts, that is, to the objects which thinking enables us to know.

— CP 1.27 (1909)

The apprehension of thought by thinking could be called ‘grasping’, but it cannot be completed—just as mind cannot be grasped—because it takes time. Since we are in time just as we are in thought, there is no way to get one ‘handle’ on either without letting go of another.

Popper and Peirce on science vs. certainty

Karl Popper, in his Logic of Scientific Discovery (originally published 1934; p. 93-4) used the metaphor of building on a swamp to emphasize that science and absolute certainty don't mix:

The empirical basis of objective science has nothing ‘absolute’ about it. Science does not rest upon solid bedrock. The bold structure of its theories rises, as it were, above a swamp. It is like a building erected on piles. The piles are driven down from above into the swamp, but not down to any natural or ‘given’ base; and if we stop driving the piles deeper, it is not because we have reached firm ground. We simply stop when we are satisfied that the piles are firm enough to carry the structure, at least for the time being.

Popper was at that time unaware that C. S. Peirce, in his Cambridge Lectures of 1898, had used the same metaphor to make the same point, though expressed with a more religious feeling for the scientific enterprise:

The only end of science, as such, is to learn the lesson that the universe has to teach it. In Induction it simply surrenders itself to the force of facts. But it finds, at once—I am partially inverting the historical order, in order to state the process in its logical order—it finds I say that this is not enough. It is driven in desperation to call upon its inward sympathy with nature, its instinct for aid, just as we find Galileo at the dawn of modern science making his appeal to il lume naturale. But in so far as it does this, the solid ground of fact fails it. It feels from that moment that its position is only provisional. It must then find confirmations or else shift its footing. Even if it does find confirmations, they are only partial. It still is not standing upon the bedrock of fact. It is walking upon a bog, and can only say, this ground seems to hold for the present. Here I will stay till it begins to give way. Moreover, in all its progress, science vaguely feels that it is only learning a lesson. The value of Facts to it, lies only in this, that they belong to Nature; and Nature is something great, and beautiful, and sacred, and eternal, and real—the object of its worship and its aspiration.

— (CP 5.589)