A non sequitur of numbing grossness

Strawson on Kant in The Bounds of Sense:

In the Second Analogy Kant expresses in a number of ways the thought that the order of perceptions of htose objective states of affairs the succession of one upon the other of which constitutes an objective change is—as, in the sense examined and with the qualifications mentioned, we see it is—a necessary order. The order of perceptions is characterized not only as a necessary, but as a determined order, an order to which our apprehension is bound down, or which we are compelled to observe. These may all perhaps be admitted as legitimate ways of expressing the denial of order-indifference. But from this point the argument proceeds by a non sequitur of numbing grossness.