The first of the Birkot Ha'shachar (morning blessings) that we recite each morning, as codified by the Shulchan Aruch (Orach Chayim 46), is "Hanoten La'sechvi Bina Le'havchin Bein Yom U'vein Layla" – "Who has given the 'Sechvi' the wisdom to distinguish between day and night."
The Mishna Berura in Orach Hayim Siman 46 (commentary to the Shulchan Aruch by the "Chafetz Chayim," Rabbi Yisrael Kagan, Lithuania, 1835-1933) mentions two possible meanings of the word "Sechvi." First, he suggests based on a verse in the Book of Iyov that "Sechvi" refers to the heart, the source of human understanding and perception. We thus thank the Almighty each morning for endowing us with the perception to make the distinction between night and day. Secondly, the Mishna Berura writes, "Sechvi" may mean "rooster." The rooster is capable of knowing the moment when day breaks, and this marks a truly wondrous feature of the natural world. According to this definition of the word, we thank God in this Beracha for endowing the rooster with this remarkable capability.
We may, however, suggest a deeper meaning of this Beracha. Our generation sorely lacks the skill of sound judgment, the ability to properly distinguish between right and wrong, between appropriate and inappropriate behavior. Lines that were clear and obvious to earlier generations have been blurred; today we encounter "gray areas" that for previous generations were clearly and unquestionably marked as right or wrong.
In this Beracha, we thank God for the ability to make judgments, to draw proper distinctions between what is acceptable and what must be rejected. "Day" and "night" in this context perhaps refer to "good" and "bad." Right as we awaken in the morning and begin our day, we offer thanks to the Almighty for this invaluable gift – the gift of sound judgment, the wisdom and understanding we need to draw the critical distinction between right and wrong.