Locke wrote:

If, by this enquiry into the nature of the understanding, I can discover the powers thereof; how far they reach; to what things they are in any degree proportionate; and where they fail us: I suppose it may be of use to prevail with the busy mind of man, to be more cautious in meddling with things exceeding its comprehension; to stop when it is at the utmost extent of its tether; and to sit down in a quiet ignorance of those things which, upon examination, are found to be beyond the reach of our capacities. We should not then perhaps be so forward, out of an affectation of an universal knowledge, to raise questions, and perplex ourselves and others with disputes about things, to which our understandings are not suited; and of which we cannot frame in our minds any clear or distinct perceptions, or whereof (as it has perhaps too often happened) we have not any notions at all. If we can find out how far the understanding can extend its view, how far it has faculties to attain certainty, and in what cases it can only judge and guess; we may learn to content ourselves with what is attainable by us in this state.

Modified version:

I hope that this enquiry into the nature of the understanding will enable me to discover what its powers are - how far they reach, what things they are adequate to deal with, and where they fail us. If I succeed, that may have the effect of persuading the busy mind of man to be more cautious in concerning itself with things that are beyond its powers to understand; to stop when it is at the extreme end of its tether; and to be peacefully reconciled to ignorance of things which turn out to be beyond the reach of our capacities. Perhaps then we shall stop pretending that we know everything, and shall not be so bold in raising questions and getting into confusing disputes with others about things to which our understandings are not suited - things of which we cannot form any clear or distinct perceptions in our minds, or, as happens all too often, things of which we have no notions at all. If we can find out what the scope of the understanding is, how far it is able to achieve certainty, and in what cases it can only judge and guess, that may teach us to accept our limitations and to rest content with knowing only what our human condition enables us to know.

Hobbes wrote:

. . . as all sorts of manufacture, so also malice increaseth by being vendible.

Modified version:

. . . malice, like everything else made by men, increases when there is a market for it.