|German polymath Johann Goethe studying in Frankfurt in the years circa 1769 to 1772 during which time he began to do experiments in chemistry in a search to uncover a secret principle of nature and the universe.|
“There is a certain secret principle in nature by which liquors are sociable to some things and unsociable to others. Thus water will not mix with oil but readily with spirit of wine or with salts.”Newton here, to note, seems to be making an unknowing citation of Empedocles and his chemical aphorisms.
The finalized efforts of Newton's search for this secret principle are found in his last and final philosophical, his 1718 Query 31, the the addendum that launched the chemical revolution.
“Chemistry is still my secret love.”
“I perceived something in nature (whether living or lifeless, animate or inanimate) that manifested itself only in contradictions and therefore could not be expressed in any concept, much less any word. It was not divine, for it seemed irrational; not human, for it had no intelligence; not diabolical, for it was beneficent; and not angelic, for it often betrayed malice. It was like chance, for it laced continuity, and like providence, for it suggested context. Everything that limits us seemed penetrable by it, and it appeared to dispose at will over the elements necessary to our existence, to contract time and expand space. It seemed only to accept the impossible and scornfully to reject the possible.”
“Das Schöne ist eine Manifestation geheimer Naturgesetze, die ohne dessen Erscheinung ewig wären verborgen geblieben.”
“The beautiful is a manifestation of secret laws of nature, which, but for its apparition, would have forever remained hidden form us.”
“Beauty is a manifestation of secret natural laws that would have remained hidden forever if the beautiful thing had not appeared.”
“Beauty is a manifestation of secret natural laws, which otherwise would have been hidden from us forever.”
See main: Adams beliefIn 1863, American thinker Henry Adams, writing to Charles Gaskell, seems to have begun searching for a universal theory of existence, applicable, in a one nature manner, atoms to humans: 
“Everything in this universe has its regular waves and tides. Electricity, sound, the wind, and I believe every part of organic nature will be brought someday within this law. The laws which govern animated beings will be ultimately found to be at bottom the same with those which rule inanimate nature, and as I entertain a profound conviction of the littleness of our kind, and of the curious enormity of creation, I am quite ready to receive with pleasure any basis for a systematic conception of it all. I look for regular tides in the affairs of man, and, of course, in our own affairs. In ever progression, somehow or other, the nations move by the same process which has never been explained but is evident in the oceans and the air. On this theory I should expect at about this time, a turn which would carry us backward.”
“My scientific work is motivated by an irresistible longing to understand the secrets of nature and by no other feeling.”IQ | Secret principle seeker