The Commens Dictionary
Quote from ‘Letters to William James’
…an assertion belongs to the class of phenomena like going before a notary and making an affidavit, executing a deed, signing a note, of which the essence is that one voluntarily puts oneself into a situation in which penalties will be incurred unless some proposition is true. One may maintain that every proposition involves an assertion. Very likely that may be true as a psychological truth; but if so the element of assertion is frequently altogether or in great degree inhibited and disavowed. I have nothing further to say about assertion.