 In the 17th century , Leibniz , Thomas <unk> and René <unk> explored the possibility that all rational thought could be made as systematic as algebra or geometry . <unk> famously wrote in Leviathan : " reason is nothing but reckoning " . Leibniz envisioned a universal language of reasoning ( his <unk> <unk> ) which would reduce <unk> to calculation , so that " there would be no more need of <unk> between two philosophers than between two accountants . For it would <unk> to take their pencils in hand , down to their slates , and to say each other ( with a friend as witness , if they liked ) : Let us calculate . " These philosophers had begun to articulate the physical symbol system hypothesis that would become the guiding faith of AI research . 
