Page:Philosophical Transactions - Volume 053.djvu/441

 Mr. Bayes has thought fit to begin his work with a brief demontration of the general laws of chance. His reaon for doing this, as he ays in his introduction, was not merely that his reader might not have the trouble of earching elewhere for the principles on which he has argued, but becaue he did not know whither to refer him for a clear demontration of them. He has alo made an apology for the peculiar definition he has given of the word chance or probability. His deign herein was to cut off all dipute about the meaning of the word, which in common language is ued in different enes by perons of different opinions, and according as it is applied to pat or future facts. But whatever different enes it may have, all (he oberves) will allow that an expectation depending on the truth of any pat fact, or the happening of any future event, ought to be etimated o much the more valuable as the fact is more likely to be true, or the event more likely to happen. Intead therefore, of the proper ene of the word probability, he has given that which all will allow to be its proper meaure in every cae where the word is ued. But it is time to conclude this letter. Experimental philoophy is indebted to you for everal dicoveries and improvements; and, therefore, I cannot help thinking that there is a peculiar propriety in directing to you the following eay and appendix. That your enquiries may be rewarded with many further uccees, and that you may enjoy every every valuable bleing, is the incere wih of, Sir,

your very humble ervant, Newington-Green, Nov. 10, 1763.