1. **State the problem:** Simplify the expression $3 + \sqrt{2}$. 2. **Understand the expression:** The expression consists of a rational number 3 and an irrational number $\sqrt{2}$. 3. **Simplification rules:** Since $3$ and $\sqrt{2}$ are unlike terms (one is rational, the other irrational), they cannot be combined further by addition. 4. **Conclusion:** The expression $3 + \sqrt{2}$ is already in its simplest form because the terms are unlike and cannot be simplified further.