For every yin, there is a yang, a wise Chinese philosopher observed a few millennia back. Probably a teacher. Similarly, for every good there is a bad. And, if you like a spaghetti western, for every good and bad, there is likely to be an ugly, too.
Certainly, this week's TES illustrates the good, the bad and the ugly in the world of education.
First there is the TES A Teaching Moment in Time project, written up in its full glory on pages 26-30.
We asked teachers around the world to stop at 11am local time a couple of weeks ago for half a minute and share with us - and the global education community - exactly what they and their classes were doing. Using email, social media and photo-sharing, thousands responded, inundating TES Towers with illustrations of their love for the job.
The unique experiment brought together the teaching profession from across the globe, providing a snapshot that demonstrated what a wonderful lot classroom practitioners are, committed both to their students and to the very idea of education.
We heard from more than 2,000 teachers in more than 50 countries across 22 time zones.
One section of the profession that was notable by its absence, however, had a very good excuse for not showing up: these people simply don't exist. They are the "ghost teachers".
"Ghost teachers" are all too real in a bureaucratic sense, as are the "ghost schools" in Pakistan where they work - 8,000 of them, according to international non-governmental organisation Transparency International. The only solid thing about these schools that exist only on paper, sadly, is the vast pile of cash they allow spivs to stash away.
These "ghost teachers" and "ghost schools" are just one manifestation of the ugly side of education. The yang to #teachingmoment's yin, if you will, is the sheer scale of corruption that exists in school systems around the world.
Billions of dollars, euros and pounds are wasted every year, according to a report due to be published next week by Transparency International (see page 8).
Bribery, embezzlement, backhanders and dodgy deals are costing the world's children dear. Endemic corruption is holding back education and development, and preventing millions of people from being lifted out of poverty. Indeed, it is the single biggest barrier to the UN Millennium Development Goal that aims to ensure that all primary-age children around the world are in school by 2015.
In addition, think of the ammunition it gives to those who would like to see countries such as the UK abandon their aid budgets.
Of course, it is easy to complain about corruption in the developing world from a comfortable office building in thoroughly modern London, but if A Teaching Moment in Time tells us anything it is that the profession is better than this.
Just ask the teachers in Cairo who emailed to tell us that they had returned to school for a voluntary team-building exercise even though the ravaged country's education system had been shut down by the military government. If that's not commitment, then I don't know what is.