Estate of O'Keefe

The contest was made on the ground of unsoundness of mind, the result of long continued intoxication. Various medical witnesses were examined upon either side; hypothetical questions were put to them, and replies were received. Referring to the testimony of these experts, the Court instructed the jury:

The testimony of experts is frequently unsatisfactory and many times unreliable. It is unsatisfactory because it cannot convey to our minds the precise reasons why the conclusions are reached; and it is unreliable because it is frequently based upon speculation instead of facts. Experts in the exact sciences and in mechanics, who base their opinions upon the laws of nature and of the exact sciences and their own experience with those laws, have tangible facts before them; but where the opinions are based upon speculation, where the subject of the inquiry, viz: the operation and condition of the human mind, is beyond the possibility of human knowledge, we should receive those opinions as at least uncertain. So, when we see a person perform such or such an act, we can form an opinion whether the act is rational or irrational, whether it is consistent with the standard of average…