David,

I my view the following passage on cumulatively change is better than 
your first passage which doesn't seem to offer much about Veblen's 
thinking on economic matters.
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The economic life history of the individual is a cumulative process 
of adaptation of means to ends that cumulatively change as the 
process goes on, both the agent and his environment being at any 
point the outcome of the last process. His methods of life today are 
enforce upon him by his habits of life carried over from yesterday 
and by the circumstances left as the mechanical residue of the life 
of yesterday.

"Why is Economics Not an Evolutionary Science?" in The Place of 
Modern Science in Modern Civilization, (New York: B. W. Huebsch, 1919)
=========================

Your second passage is one of Veblen's more famous quotations and it 
does illustrate elements of Veblen's style and thinking. In my view, 
however, the following quotation might be a better passage from the 
point of view of illustrating Veblen's evolutionary thinking. I 
realize that many people like the "hedonistic conception of man" 
quote, so it's probably a toss up which of the two is "better."
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In economic life, as in other lines of human conduct, habitual modes 
of activity and relations have grown up and have by convention 
settled into a fabric of institutions. These institutions ... have a 
prescriptive, habitual force of their own .... If the contrary were 
true, if men universally acted not on the conventional grounds and 
values afforded by the fabric of institutions, but solely and 
directly on the grounds and values afforded by the unconventionalised 
propensities and aptitudes of hereditary human nature, then there 
would be no institutions and no culture. But the institutional 
structure of society subsists and men live within its lines, with 
more or less questioning, it is true, but with more acquiescence than dissent.

"Fisher's Rate of Interest," Political Science Quarterly, vol 24, 
(1909) Reprinted in "Essays in our Changing Order" (New York: 
Augustus M. Kelley, 1964), p. 143.
=========================

Your third passage is nice because it comes from an essay that 
illustrates an application of Veblen's evolutionary views. It's too 
bad that the role of competition in the modern form of emulative 
behavior can't be added to the quote. Anyway, the following corrects 
the quotation by adding ellipses where required and notes the full 
title of the essay.
-------------------------
Human nature being what it is, the struggle of each to possess more 
than his neighbor is inseparable from the institution of private 
property. ... The inference seems to be that ... there can be no 
peace from this--it must be admitted--ignoble form of emulation, or 
from the discontent that goes with it, this side of the abolition of 
private property.

"Some Neglected Points in the Theory of Socialism" Annals of the 
American Academy of Political and Social Science, Vol. 2 (Nov., 
1891), pp. 57-74. Reprinted in The Place of Science in Modern 
Civilization, p. 391.
=========================

Michael Nuwer