Back in May, northern Berkshire county had an infestation of tent caterpillars. I'd never been unduly bothered by tent caterpillars before; I actually found them kind of pretty, once upon a time. (Singly, mind you. In twos and threes.) But once they emerged by the hundreds and thousands, my aesthetic appreciation waned. The exterior of our house swarmed. The contractor who was doing some repair work on an exterior wall brought his digital camera to take pictures, because he'd never seen anything like it. It didn't take long before I felt besieged.

In short order, the caterpillars ate every shred of green in sight. Our valley was denuded. The blueberry bushes we'd nursed through a cold winter, the new lilacs we'd put in -- every last thing in sight was stripped to twigs. We don't grow any of our own food at home, and (baruch Hashem) the organic community-supported farm to which we belong wasn't affected by the caterpillars, so that harvest wasn't destroyed. Our food supply was guaranteed, and our health was never in question.

Even so, I found the caterpillars strangely unsettling, as if the earth had tilted on its axis and the benevolent universe weren't quite trustworthy anymore. For a few weeks, I was miserable. The loss of spring's precious green affected me emotionally, and I was unaccountably sad every time I looked out the window or left the safe harbor of our house. I still worry in my dreams that our house is seeded with their cocoons. That was a single plague, and it only affected me in visual and emotional ways, but it struck deep.

So this year, as we read about the infliction of the ten plagues upon the Egyptians, I shudder in ways I hadn't, before. Knowing how distressing I found a single infestation, I can begin to imagine the impact of the ten plagues on the Egyptian people.

Pharaoh's heart, we read, was repeatedly hardened, and therefore he refused to let the Israelites be free. Many commentators have suggested that he did the initial work of hardening his own heart, through evil acts which deadened his sense of compassion, and that God only participated in that hardening once Pharaoh had damaged his own ability to make teshuvah. But what of ordinary Egyptians? We learned last week that they feared the Israelites, and that they therefore made the Israelites' lives bitter with hard labor. Is this the equivalent of hardening their hearts, as Pharaoh had done? Did they ever imagine that these plagues were punishment, or were they bewildered by these progressive waves of ill fortune? Were they wicked, or just unable to see their role in perpetuating the ills of a badly broken system?

It's one thing to engage this kind of "karmic theology," which suggests that calamity is necessarily punishment for sin, in our texts. It's another thing to encounter it in modern-day life (remember some of the rhetoric that followed in the wake of hurricane Katrina?) I find the argument that natural disasters are punishment for wickedness disturbing on any scale, whether the disaster in question is an excess of creepy-crawlies or a string of devastating hurricanes. But I can believe that when we ignore signs of climate change in our time, we may resemble the Egyptians more than we want to admit.

The plagues can be understood as a kind of deadly imbalance, each "an aspect of the God-force that is broken off from the Tree [of Life]." (So writes Rabbi Shefa Gold in her new book Torah Journeys.) Our challenge, she writes, is to witness plagues without entering into compassion fatigue -- without closing ourselves off from the suffering inherent in our imbalanced world. Only through facing prolonged suffering with our eyes and hearts open can we avoid the danger of our own hearts calcifying. A hard heart is too heavy; in the journey toward liberation, it behooves us to overflow with compassion, to travel light...and to look closely at what patterns of our own may be creating and sustaining deadly imbalances in our own day.