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  • Writer's pictureBradley Cook

The Jewish People are Divided … Here’s How To Fix It: Terrarium Design

Updated: Jul 7, 2022

By Bradley Caro Cook, Ed.D. from


Rabbi Hillel instructs us not to separate from the community (Pirke Avot, 2:4). This is often interpreted as an individual or small faction not seperating from the community at large. Yet, I’d like to provide an alternative interpretation. Rather than separating from the overall community, we as a community separate ourselves from within. Then we ask ourselves, “Why are we so divided?”

Research indicates that to function within the world, we create new categories. The same research indicates this is damaging as these silos yield intergroup bias, communal division, and serve as a breeding ground for prejudice (Dhont, Roets, & Hiel, 2011).

A Psychological Need to Divide

From where does human-made division and prejudice stem? Not from ideology; rather, it comes from a deeper psychological need to categorize (Dhont, et. al).

Two Categories of Jewish Division

The first step of overcoming these division-based prejudices is by first identifying the divisions that caused them. Let’s take a look at these two categories: Creator-made vs human-made:

The Creator of the Universe, according to Jewish tradition, established eternal divisions as a design within creation. These divisions therefore serve a meaningful purpose. Human-made divisions, which stem from our psychological need to categorize, inadvertently yield division and unintentionally result in prejudice and intergroup bias.

Creator Made Divisions

There are divisions embedded in Judaism that lay the base schema to understand and function within the world. These are:

Day and NightHeaven and EarthHoly and MundaneShabbat and the WeekCelestial Beings and HumansMan and WomanJew and GentileThe 12 Tribes (Genesis 49:28)Child and AdultCohen and LeviOrphan, widow, convertCommandments and Transgressions …to name a few.

Then, there are the divisions that we, as Jewish communal professionals, have created, designed for, and our communities have subscribed to over the past 3,500 years.

Examples of Human–Made Divisions (Separating the Community)

Korach’s Rebellion (Pirke Avot, 5:17)Establishing Kingship (Samuel, 1:8)Sadducees and EssenesYerushalmi/BavliAshkenazi/SephardiIsrael/DiasporaSecular and ReligiousReform/Conservative/Reconstructionist/Modern Orthodox/Chabad (etc).Frum From Birth/Baalei TshuvaYoung Adults (in their 20s and 30s) and 45+ AdultsProgressive/TraditionalThe Parties in the Israeli ParliamentAnd the list of divisions goes on and continues to increase…

Psychological Research and Talmudic Wisdom

What can we do as Jewish communal professionals to decrease our human-made divisions and unite the Jewish people? What can we do to fulfill the ever so referenced charge that all Israel is responsible for one another (Shavuot, 39a)?

Positive Psychology

Extensive research shows that if we create frequent positive interactions between members of different groups, over time the division between these groups dissipates, and on a psychological level, the divisions and biases dissipate as well (Allport, 1954; Brown & Hewstone, 2005; Dovidio, Gaertner, & Kawakami, 2003; Pettigrew, 1998 as cited in Dhont, Arne, & Alain Van Hiel, 2011).

Talmudic Alignment: An Exception for Human-Made Division Which Includes the Hint of a Solution

One human-made division is referenced as an acceptable kind of division, that of Bet Hillel and Bet Shammai, which was for Heaven’s sake (Pirke Avot, 5:17). This Mishnaic exception is expounded in a Talmudic lesson that hints at the model solution. “Bet Hillel and Bet Shammai, when it came to marrying the offspring of their houses, removed their division. This teaches that they practiced love and camaraderie between them (Yevamot, 14b:10).” While their division for the sake of heaven remained, they intentionally practiced the removal of this division for the continuity of the Jewish people. We can follow their lead.

Not Waiting for Crisis

Typically, we experience unity when there is a crisis that affects a Jewish community or the Jewish people as a whole. Anti-semitism, kidnapping, oppression, etc. We all come together for that moment, but rather than unify even more following, we and then divide again. Rather than having reactive unity, we can intentionally design proactive-unity by creating moments of grassroots-unity that remove human created division.

A New Paradigm: Terrarium Design

Based upon Talmudic wisdom and positive psychology, I introduce a new design methodology which Jewish communal professionals can use to increase Jewish unity: Terrarium Design.

A terrarium functions harmoniously when it has all of the necessary components of creation: water, air, creatures, plants, and light. The only divisions necessary in a terrarium are the divisions that are part of creation. If you separate one of these elements from the ecosystem, the ecological harmony will be disrupted and life will eventually cease.

A community is similar to a terrarium, for just as a terrarium thrives where there are positive interactions between all of its ecological elements, so too does a Jewish community. This is the Jewish concept of achdoot or unity.

What Organizations Can Benefit from Terrarium Design?

Terrarium design can benefit all Jewish organizations, even if the target audience is siloed (i.e. young adults). For research indicates not to remove silos, rather to increase positive interactions between divided groups.

How Can We Get Started?

Well, I’m glad you asked. I suggest starting with a series of three questions:

Step 1: Pinpointing the Divisions in the Community Question Set 1: What are divisions that exist within your organization’s programs?

What are your human-made divisions? (list them)

Eg. Israel vs Diaspora, young adults vs. seasoned adults, secular Jews vs religious Jews, or denomination specific, etc.

What are your Creator made divisions? (list them)

Eg. Women vs Men, Shabbat Vs. Week, Child vs Adult, Shabbat vs Week, Mundane vs Secular, etc.

Note: Creator made divisions do NOT divide the community, and thus do not need to be removed for Terrarium Design. For example, randomly putting 5-year-olds together with 35-year-olds does not support this design model as Child and Adult are two Creator-made divisions. Or removing a Creator-made division such as that between Cohen and Levi would NOT support Terrarium design. Another example is when it comes to Sisterhood and Brotherhood, or a Jewish Fraternity and Sorority. Dividing men and women DOES align with Creator-made division and is thus okay.

Step 2: Removal of Human Made Divisions

Question: Which human made division(s) that you’d like to remove for one specific program? (tip=start small)

For example, we noticed early on in Career Up Now that the programs and cohorts that were intergenerational were the ones that had the greatest impact on communal unity. So now, while our primary audience remains emerging professionals, all of our programs engage adults spanning 5 generations. We removed the human-made adult-division which decrease the ageism bias. This strengthens local Jewish communities and addresses the problem described in Dahlia Bendavid’s poingant article “Over 45 and Invisible.”

Step 3: Identify Partners and Design Positive Group Interactions

Question 3: With which organizations can we partner and co-create to encourage interactions between groups outside of our target audience?

For example, Career Up Now partnered with JQ International and Jewish Big Brothers Big Sisters of Los Angeles (the Bigs) to create an intergenerational and mixed-orientation program which increased positive interactions between these human-separated groups (college students/professionals/gender orientation).

Another Example

Masa Israel Journey partnered with Career Up Now to create the Masa Innovation Forum which brought together Masa alumni and industry leaders intergenerationally, both those from Israel and the Diaspora. This terrarium design created positive interactions between three human-divided groups:

Young adults and 45+ adultsIsraelis and American Jews (in the diaspora)Israelis (in Israel) and American Jews

Thus we decreased age, geographic, and cultural biases.

Organizations Leading the Way

There are many organizations and initiatives that are leading the way in comprehensively designing programs that bring together individuals for positive interactions.

Hazon Intentional Community Incubator: Which works with individuals and organizations to create intentional communities in their local communities.Geula Gathering: A new global women’s initiative bringing together tens of thousands of women across ages, geographic locations, and denominations to create Jewish unity and bring the ultimate Jewish redemption.ROI Community: A global community of Jewish leaders who are shaping the future of the Jewish world.Career Up Now: Jewish wisdom-based career advancement communities that strengthen local communities.Limmud: Creates Jewish learning gatherings that advance Jewish journeys.Hadar-Singing Communities: Welcoming all with a voice.The Associated Jewish Community Federation of Baltimore – a federation who successfully engages and supports cross denominationally.

I’m interested to hear what other organizations are actively removing silos and barriers in the creation of their programs.


In conclusion, I welcome all Jewish communal professionals to try Terrarium Design, to decrease the walls that divide, and bring together the Jewish people as one. For then we can we follow in the footsteps of Bet Hillel and Bet Shammai fulfilling the prophetic song of ascent: How good and how pleasant it is when we dwell together (Psalms, 133:1).

Bradley Caro Cook, Ed.D., believes there are simple solutions to complex Jewish problems at the intersection of Positive Psychology and applied Jewish wisdom. He is the co-founder of Career Up Now, A Birthright Israel Fellow, UpStart alumnus, Eli Talks Fellow, a member of the Schusterman ROI Community, a member of the Hazon Intentional Community Incubator and Glean’s Spiritual Entrepreneurship Incubator. Everyday Bradley advances new forms of Jewish learning and meaningful Jewish engagement. He is pioneering Growth Hacking for Jewish Engagement and other novel ideas. Bradley can be reached via email:

References: Dhont, K., Roets, A., & Hiel, A. V. (2011). Opening Closed Minds: The Combined Effects of Intergroup Contact and Need for Closure on Prejudice. Personality and Social Psychology Bulletin, 37(4), 514-528. doi:10.1177/0146167211399101

Dhont, K., Hiel, A. V., & Hewstone, M. (2013). Changing the ideological roots of prejudice: Longitudinal effects of ethnic intergroup contact on social dominance orientation. Group Processes & Intergroup Relations,17(1), 27-44. doi:10.1177/1368430213497064

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