In the realm of public policy making, 'Rationalism' and 'Incrementalism' represent two fundamentally contrasting approaches to how policies are formulated and implemented. While rationalism posits an ideal, comprehensive decision-making process, incrementalism offers a more pragmatic and realistic view of policy development, making them theoretical opposites.

Rationalism (The Rational-Comprehensive Model): This model, often considered an ideal or normative approach, assumes that policy-makers have clear, consistent, and ranked goals. The process involves:

1. Problem Definition: Clearly identifying and defining the policy problem.
2. Goal Setting: Establishing specific, measurable, achievable, relevant, and time-bound (SMART) objectives.
3. Information Gathering: Collecting all relevant information and data related to the problem and potential solutions.
4. Alternative Generation: Identifying and considering all possible policy alternatives to achieve the goals.
5. Consequence Analysis: Thoroughly analyzing the costs, benefits, and consequences (both intended and unintended) of each alternative.
6. Optimal Choice: Selecting the alternative that maximizes benefits and minimizes costs, leading to the most efficient and effective outcome.

Rationalism assumes perfect information, unlimited time and resources for analysis, and the ability of decision-makers to objectively evaluate all options. It aims for a comprehensive, optimal solution.

Incrementalism (The Incremental Model or 'Muddling Through'): Championed by Charles Lindblom, incrementalism offers a descriptive and more realistic account of policy-making. It acknowledges the practical limitations faced by policy-makers and suggests that policy decisions are typically made through small, marginal adjustments to existing policies. Key characteristics include:

1. Bounded Rationality: Policy-makers operate with limited information, time, and cognitive capacity.
2. Satisficing: Instead of seeking the optimal solution, policy-makers aim for a 'satisficing' solution – one that is good enough and politically acceptable.
3. Limited Alternatives: Only a few alternatives, usually those marginally different from existing policies, are considered.
4. Successive Limited Comparisons: Policy-making is a process of continuous adjustment and re-adjustment, comparing the consequences of small changes rather than a comprehensive re-evaluation of fundamental goals.
5. Political Feasibility: Policy choices are heavily influenced by political considerations, bargaining, and compromise among various stakeholders.

The Opposition: The fundamental opposition between rationalism and incrementalism lies in their core assumptions and processes:

• Scope: Rationalism is comprehensive, seeking to re-evaluate entire policy frameworks, while incrementalism is limited, focusing on minor adjustments.
• Information: Rationalism assumes full information; incrementalism acknowledges bounded rationality and incomplete information.
• Goals: Rationalism requires clear, stable, and ranked goals; incrementalism sees goals as often vague, conflicting, and evolving through the policy process.
• Change: Rationalism can lead to radical, transformative change; incrementalism favors gradual, evolutionary change.
• Feasibility: Rationalism is often idealistic and difficult to achieve in practice; incrementalism is pragmatic and politically feasible.

In conclusion, while rationalism provides an ideal benchmark for policy-making, its demands are rarely met in the complex, uncertain, and politically charged real world. Incrementalism, with its focus on practical constraints and adaptive adjustments, offers a more accurate description of how most public policies are actually made. Thus, they stand as conceptual opposites, representing the ideal versus the real in policy formulation.