David on Ambiguity

“The chief obstacle... to our improvement in the moral and metaphysical sciences is the obscurity of the ideas, and ambiguity of the terms.”

“From this circumstance alone, that a controversy has been long kept on foot, and remains undecided, we may presume that there is some ambiguity in the expression, and that the disputants affix different ideas to the terms employed in the controversy.”

“By what invention can we throw light upon these ideas, and render them altogether precise and determinate to our intellectual view? Produce the impressions or original sentiments, from which the ideas are copied. These impressions are all strong and sensible. They admit not of ambiguity. They are not only placed in full light themselves, but may throw light on their correspondent ideas, which lie in obscurity.”

“The finer sentiments of the mind, the operations of the understanding, the various agitations and passions, though really in themselves distinct, easily escape us, when surveyed by reflection; nor is it in our power to recall the original object, as often as we have the time to contemplate it. Ambiguity, by this means, is gradually introduced into our reasonings; similar objects are readily taken to be the same: the conclusion becomes at last very wide of the premises.”

“If men attempt the discussion of questions which lie entirely beyond the reach of human capacity, such as those concerning the origin of worlds, or the economy of the intellectual system or region of spirits, they may long beat the air in their fruitless contests, and never arrive at any determinate conclusion. But if the question regard any subject of common life and experience, nothing, one would think, could preserve the dispute so long undecided but some ambiguous expressions, which keep the antagonists still at a distance, and hinder them from grappling with each other.”