René Descartes, the French mathematician, scientist and philosopher, is famous for many things, such as inventing the rectangular coordinate system we use to graph equations.

It is likely that many of us learned of him in an algebra class because he was the creator of this Cartesian coordinate system, named as such in his honor. He is also considered to be the father of modern Western philosophy and his most famous saying might be the Latin phrase “cogito ergo sum”, translated to English as, “I think, therefore I am.” His idea was that thinking about or doubting one’s existence is proof that we exist.

I don’t know anyone who doesn’t think, although I know some people that I don’t agree with on what they think and that’s what makes life interesting most of the time and frustrating some of the time.

When it comes to the existence of some of our nonhuman friends, thinking about them or being thought about by them is often a result of observation or interaction. We are no doubt in the minds of other animals when we cross paths with them as they approach us for friendship and food, run for fear of being hunted, stepped on or otherwise harmed for some reason, or attack us because we are too close to their homes.

Many people don’t think about other organisms unless they are encountered in their lives. For example, in Tucson I can forget about mosquitoes until they are biting me during the monsoon. And I realize it’s a certain time of year when I see rufous hummingbirds at my feeders.

I expect that we are all curious enough about some things to spend time thinking about them, especially those of us who in our spare time enjoy the natural world in some way or another.

I like to hike, read, observe plants and animals, keep records, learn by doing, and discuss with others what I find interesting. Of course, there are many things to do and learn in this world and we don’t have time for them all. As some of my Pennsylvania Dutch ancestors would say, “We are too soon old, and too late smart” so I don’t plan to spend much time on things I care little about.

I was raised by a family of naturalists and family outings often included hikes, catching bugs, and trying to identify birds and plants along the way. Those skills are what drove me to become an entomologist. I feel like I exist when thinking about these other organisms in our environment. It’s exciting and energizing to see and sometimes feel their presence and realize that I am part of an ecosystem. I encourage anyone I know to take in as much of the natural world as time and ability allows.

In 2016, a few friends and colleagues with like minds put together a new statewide program called the Arizona Master Naturalist Association (www.azmasternaturalist.org). Last spring in Pima County we held our first training class with our partners at Pima County Natural Resources, Parks and Recreation, the USA National Phenology Network, and the Ironwood Tree Experience.

The association’s goal is to build a corps of volunteers able to contribute expert hours to existing natural resource projects in citizen science, stewardship and education. Grounded in science, environmental education and interpretative concepts, the core curriculum provides trained volunteers the skills to not just volunteer but to become natural resource leaders. Using a systems-based approach, each chapter’s curriculum is designed to educate participants about local ecosystems. In Tucson, the course helps volunteers learn more about the Sonoran Desert ecosystem. Certified participants now contribute their knowledge about the natural world to our local parks and other natural resource organizations in need of volunteers. As of now the course boasts 23 trained volunteers, 14 of whom have become fully certified by contributing more than 60 hours of time to local organizations and agencies. In total, the course participants have contributed more than 1,600 hours of volunteer service to our partners in Tucson since January 2017.

The start of a continuing adventure, the second 18-week training cohort is scheduled to begin on Jan. 10. If you are interested in learning more about the program or applying to join us, visit www.azmasternaturalist.org/pima-county for details on how you can be involved.

I’ve written in this space many times about how to manage animal and plant intrusions into our cultivated places. Now I would like to spend some time on the natural world, including animals and plants we encounter either on purpose as we hike through their habitats or as we observe them from our own back yards. I’ve got some ideas already and am open to others — if there are questions about what you see and find, encounters you’d like to share or things that should be mentioned according to you, the reader, I’d love to hear them.

Peter Warren is an entomologist and a board member of the Arizona Master Naturalist Association. Contact him at tucsongardensage@gmail.com